M2compiler-V3/compiler/src/M2.lst

Coco/R - Compiler-Compiler V1.53
Released by Pat Terry 17 September 2002
Source file: M2.atg

Grammar Tests:

Deletable symbols:
     DeclSeq
Undefined nonterminals:   -- none --
Unreachable nonterminals: -- none --
Circular derivations:     -- none --
Underivable nonterminals: -- none --
LL(1) conditions:
 LL(1) error in ProcTypeSection: ident is the start of several alternatives.
 LL(1) error in TypeBlock: "CLASS" is the start & successor of a deletable structure

Listing:

    1  COMPILER M2
    2  (* Step 1 — minimal integer pipeline (m2compiler-V3).
    3     Subset: program MODULE + CONST (literal) + VAR INTEGER +
    4     assignment + integer expressions (+ - * DIV MOD, leading sign,
    5     parens). Fresh QBE backend (QbeGen) to gen_ssa/<Module>.ssa;
    6     assemble with qbe, link with cc.
    7  
    8     Test convention: a global VAR ExitCode : INTEGER makes generated
    9     $main return its value as the process exit code, else return 0.
   10  
   11     Semantic errors reuse the V1/V2/Test2 family: 200 duplicate,
   12     201 undeclared, 202 module name mismatch, 210 bad assignment,
   13     211 bad arithmetic, 221 not a type, 230 not supported yet,
   14     231 opaque type outside definition.
   15     Scalar-phase TYPEs (named, integer subrange, enum) check fully;
   16     composite forms wait for step 3.    Procedure headings (formals,
   17     result, FORWARD) enter scopes now; bodies parse + check with one
   18     230 at END (lowering = step 4).
   19     Statements: assignment, IF/ELSIF/ELSE, WHILE, REPEAT/UNTIL,
   20     LOOP/EXIT (230 outside LOOP), FOR/TO/static-sign-BY, full CASE
   21     (labels, ranges, ELSE; compare-chain), RETURN with 232 checks
   22     (outside proc / value mismatch / missing value). WITH waits for
   23     records (step 3). Boolean connectives are eager (or/and/xor);
   24     relations yield 0/1 via cXXw.
   25     Clarion-form classes (docs/OOP.txt): CLASS decl + single
   26     inheritance + CLASS IMPLEMENTATION blocks, methods with ";"
   27     (per the Table example, not the sketch's ","), VIRTUAL flagged.
   28     Scopes and member checks now; lowering later (one 230 per
   29     class/impl block). Classic identifiers: no underscores, so the
   30     Table example's _names stay lexically out of reach.
   31     Step 3.1 arrays: "ARRAY [lo..hi, ...] OF T" (folded literal
   32     bounds, int/char) and open "ARRAY OF T" formals; index suffixes
   33     with per-level checks (217/218, trap on breach via $abort);
   34     whole-array ":=" with runtime count check + blit; string
   35     literals lower as descriptors (1-char stays CHAR, empty works);
   36     array/string "=" is 213 (no built-in whole comparison).
   37     Step 3.3 sets: multi-word masks (no header, static words) over
   38     bases ≤ 256 values; literals are SET OF [0..255] (222 on
   39     out-of-span); + - * / as or/and/xor-not, IN with span trap,
   40     =/# word-wise (lenient cross-base); CASE labels reject sets.
   41     Step 3.4 records: flat blobs; array fields are pointers to static
   42     descriptors (locked amendment — one layout per type); nested
   43     records inline; static declaration-order offsets; field chains
   44     mix with indexes; WITH pushes fields + bases (215/216);
   45     whole-record deep copy; record/set/class "=" is 213.
   46     Step 3.6 pointers: vars (l), NIL as a real type (FNil — assignment
   47     and =/# work, everything else 210-214/222), ^ deref with sfx
   48     discipline (address flows, load at use; chains compose),
   49     pointer =/# via ceql/cnel (< > etc. are 213), NEW/DISPOSE as
   50     builtin statements via extern malloc/free (recursive skeleton
   51     init; DISPOSE shallow and nils, deviating from Wirth-undefined);
   52     nil-deref is raw (no check). *)
   53  
   54  IMPORT SymTab, QbeGen, AST, Lower;
   55  
   56  VAR
   57    (* Two-phase frontend (docs/plan-two-phase.md).  When TRUE the
   58       productions ALSO build AST nodes alongside the legacy emit path.
   59       Slice 1: the nodes are inert scaffolding — nothing reads them, so
   60       the emitted output is unchanged. *)
   61    twoPhase: BOOLEAN;
   62  
   63    (* Result slot for the expression-AST builder (slice 2).  Every
   64       Expr/SimExpr/Term/Fact leaves its node here; the combination
   65       productions save it into locals before parsing the next operand.
   66       `astIsLit` in Fact is per-invocation, so a nested Fact cannot make
   67       an outer non-literal Fact look literal. *)
   68    astCur: AST.Node;
   69  
   70    (* Actual-argument nodes collected by ActParam for the call being
   71       parsed by ArgList (slice 4).  Fact resets the count before the
   72       optional ArgList and then folds the nodes into an NkCall. *)
   73    astNArgs: CARDINAL;
   74    astArgs: ARRAY [0 .. 31] OF AST.Node;
   75  
   76    (* Statement-AST result slot (slice 5): the most recently parsed
   77       statement.  StatSeq folds these into an NkBlock. *)
   78    astStmt: AST.Node;
   79  
   80    (* Declaration-AST result slot (slice 6): the most recently built
   81       declaration; DeclSeq folds these into an NkDeclSeq. *)
   82    astDecl: AST.Node;
   83  
   84    (* The local declarations of the most recent Block (a procedure body);
   85       ProcDecl stores them as the proc node's child 2. *)
   86    astBlkDecls: AST.Node;
   87  
   88    (* Unit-AST root (slice 7): NkUnit(name, decls, body). *)
   89    astUnit: AST.Node;
   90  
   91    (* Test-only: when TRUE the program unit is re-emitted from the AST via
   92       Lower right after the legacy EndModule (before EndUnit closes the
   93       module scope, so Lower can still resolve names). *)
   94    lowerRequested: BOOLEAN;
   95  
   96    (* Import accumulator (slice 11): `{ Import }` appends NkImport
   97       nodes here; each unit stores them as NkUnit child[3]. *)
   98    astImp, astImpTail: AST.Node;
   99  
  100    (* Class-AST accumulators (slice 13): the class node currently being
  101       parsed and its parent/field/method lists.  Classes are not nested
  102       inside one another, so module-level state is safe. *)
  103    astCls, astClsP, astClsPTail, astClsF, astClsFTail,
  104    astClsM, astClsMTail, astMethod: AST.Node;
  105  
  106    (* Class of the method named by the last `obj.Method` designator
  107       (InvalidType when the callee is an ordinary procedure). Set by
  108       Design, consumed by the following ArgList. *)
  109    methCls: SymTab.TypeIndex;
  110    (* Class of the type of the innermost `TypeName{...}` brace
  111       constructor (ClSet or ClArray); dispatches BraceElem. *)
  112    braceCls: INTEGER;
  113    (* Module-level VAR declarations whose type was still an unresolved
  114       forward alias at declaration time; emitted once the TYPE block
  115       completes (module scope only). *)
  116    nPendVar: CARDINAL;
  117    pendVarName: ARRAY [0 .. 255] OF SymTab.Name;
  118    pendVarT: ARRAY [0 .. 255] OF SymTab.TypeIndex;
  119    (* Forward module-level variables referenced from a procedure body. *)
  120    nFvarRefs: CARDINAL;
  121    fvarId: ARRAY [0 .. 255] OF INTEGER;
  122    fvarSlot: ARRAY [0 .. 255] OF INTEGER;
  123  
  124  PROCEDURE FlushPend;
  125  (* Emit module-level globals whose forward type is now resolved. *)
  126    VAR k: CARDINAL;
  127    BEGIN
  128      k := 0;
  129      WHILE k < nPendVar DO
  130        QbeGen.DeclVar(pendVarName[k], pendVarT[k]);
  131        INC(k)
  132      END;
  133      nPendVar := 0
  134    END FlushPend;
  135  
  136  PROCEDURE FwdVarNote (id, slot: INTEGER);
  137    BEGIN
  138      IF nFvarRefs <= HIGH(fvarId) THEN
  139        fvarId[nFvarRefs] := id;
  140        fvarSlot[nFvarRefs] := slot;
  141        INC(nFvarRefs)
  142      END
  143    END FwdVarNote;
  144  
  145  PROCEDURE FwdVarFlush;
  146  (* At module end: resolve every forward reference against the declared
  147     names (an unresolved one is 201) and patch its placeholder symbol. *)
  148    VAR k: CARDINAL; nm, g: SymTab.Name; cls: INTEGER; oper: CHAR;
  149        t: SymTab.TypeIndex; ok: BOOLEAN;
  150    BEGIN
  151      k := 0;
  152      WHILE k < nFvarRefs DO
  153        SymTab.FwdVarName(fvarId[k], nm);
  154        IF nm[0] # CHR(0) THEN
  155          IF NOT SymTab.FwdVarResolve(fvarId[k]) THEN
  156            SemError(201)
  157          ELSE
  158            t := SymTab.FwdVarType(fvarId[k]);
  159            cls := SymTab.ClassOf(t);
  160            IF cls = SymTab.ClReal THEN oper := "d"
  161            ELSIF SymTab.IsLongFamily(t) THEN oper := "l"
  162            ELSE oper := "w"
  163            END;
  164            ok := SymTab.GlobalRef(nm, g);
  165            QbeGen.FwdPatch(fvarSlot[k], fvarSlot[k], nm, oper, ok)
  166          END
  167        END;
  168        INC(k)
  169      END;
  170      nFvarRefs := 0
  171    END FwdVarFlush;
  172  
  173  PROCEDURE AstAppend (kind: INTEGER; VAR head, tail: AST.Node;
  174                       item: AST.Node);
  175  (* Appends `item` to a chunked sequence: each node holds up to
  176     AST.MaxChild-1 items; child[MaxChild-1] continues into the next
  177     chunk.  Unbounded, so blocks/decl sequences are not capped at 8. *)
  178    VAR n: AST.Node;
  179    BEGIN
  180      IF item = AST.NoNode THEN RETURN END;
  181      IF head = AST.NoNode THEN
  182        head := AST.MakeNode(kind); tail := head
  183      END;
  184      IF AST.NChild(tail) >= AST.MaxChild - 1 THEN
  185        n := AST.MakeNode(kind);
  186        AST.SetChild(tail, AST.MaxChild - 1, n);
  187        tail := n
  188      END;
  189      AST.SetChild(tail, AST.NChild(tail), item)
  190    END AstAppend;
  191  
  192  PROCEDURE AstCallNode (callee: AST.Node) : AST.Node;
  193  (* Builds NkCall(callee, actuals...) from astArgs/astNArgs.  The actuals
  194     are a chunked sequence (AstAppend): a call can have more than
  195     MaxChild-1 arguments (the generic ArgList has 9), and SetChild would
  196     silently drop the tail.  NkBlock marks the continuation chunks. *)
  197    VAR n, tail: AST.Node; j: CARDINAL;
  198    BEGIN
  199      n := AST.MakeNode(AST.NkCall);
  200      AST.SetChild(n, 0, callee);
  201      tail := n;
  202      j := 0;
  203      WHILE j < astNArgs DO
  204        AstAppend(AST.NkBlock, n, tail, astArgs[j]);
  205        INC(j)
  206      END;
  207      RETURN n
  208    END AstCallNode;
  209  
  210  
  211  
  212  PROCEDURE GetUnit (): AST.Node;
  213  (* The most recently parsed unit's AST root (for the Lower comparison). *)
  214    BEGIN
  215      RETURN astUnit
  216    END GetUnit;
  217  
  218  PROCEDURE SetLower (b: BOOLEAN);
  219  (* Enables the test-only Lower re-emit at program-unit end. *)
  220    BEGIN
  221      lowerRequested := b
  222    END SetLower;
  223  
  224  CHARACTERS
  225    eol      = CHR(13) .
  226    lf       = CHR(10) .
  227    letter   = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" .
  228    digit    = "0123456789" .
  229    hexDigit = digit + "ABCDEFabcdef" .
  230    noQuote1 = ANY - "'" - eol .
  231    noQuote2 = ANY - '"' - eol .
  232  
  233  IGNORE CHR(9) .. CHR(13)
  234  
  235  COMMENTS FROM "(*" TO "*)" NESTED
  236  COMMENTS FROM "//" TO lf
  237  
  238  TOKENS
  239    ident   = letter { letter | digit | "_" } .
  240    integer = digit { digit }
  241            | digit { digit } CONTEXT("..")
  242            | "0x" hexDigit { hexDigit }
  243            | "0X" hexDigit { hexDigit } .
  244    real    = digit { digit } "." { digit }
  245              [ ( "E" | "e" ) [ "+" | "-" ] digit { digit } ] .
  246    string  = "'" { noQuote1 } "'"
  247            | '"' { noQuote2 } '"' .
  248    charConst = digit { digit } ( "C" | "c" ) .
  249    ustring = ( "U" | "u" ) ( "'" { noQuote1 } "'" | '"' { noQuote2 } '"' ) .
  250  
  251  PRODUCTIONS
  252    M2
  253      = (. twoPhase := TRUE; astCur := AST.NoNode; astStmt := AST.NoNode; astDecl := AST.NoNode; astImp := AST.NoNode; astImpTail := AST.NoNode;
  254                                             astImp := AST.NoNode;
  255                                             astImpTail := AST.NoNode; .)
  256        Unit "." .
  257    (* Units: program modules compile fully; DEFINITION and
  258       IMPLEMENTATION modules parse + check now but lower in step 4
  259       (each ends with one 230); same for nested local modules. *)
  260    Unit
  261      = DefUnit
  262      | ImplUnit
  263      | ProgModule .
  264    (* Step 4.3: one session compiles DEFINITION, its IMPLEMENTATION
  265       and one program (last) into one image. Units share the symbol
  266       table; imports materialize exported names. *)
  267    DefUnit                               (. VAR m1, m2, pn: SymTab.Name;
  268                                               astSeq, astTail, astProc: AST.Node; .)
  269      = "DEFINITION" "MODULE"
  270        GetIdent<m1>                      (. IF NOT SymTab.BeginDef(m1) THEN
  271                                               SemError(200) END;
  272                                             QbeGen.SetModule(m1); .)
  273        ";"
  274        { Import                        (. AstAppend(AST.NkDeclSeq,
  275                                               astImp, astImpTail, astDecl); .) }
  276        [ "EXPORT" [ "QUALIFIED" ]        (. (* definition-module export
  277                                                list: parsed, and the
  278                                                names are already exported
  279                                                by the module scope *) .)
  280          GetIdent<pn> { "," GetIdent<pn> } ";" ]
  281                                          (. astSeq := AST.NoNode;
  282                                             astTail := AST.NoNode; .)
  283        { ConstBlock                      (. AstAppend(AST.NkDeclSeq,
  284                                               astSeq, astTail, astDecl); .)
  285        | TypeBlock<TRUE>                 (. AstAppend(AST.NkDeclSeq,
  286                                               astSeq, astTail, astDecl); .)
  287        | VarBlock                        (. AstAppend(AST.NkDeclSeq,
  288                                               astSeq, astTail, astDecl); .)
  289        | ProcHeading<pn, SymTab.InvalidType> ";"
  290                                          (. (* a heading only: record it so
  291                                                Lower can replay it *)
  292                                             astProc := AST.MakeNode(AST.NkProcDecl);
  293                                             AST.SetOp(astProc, 0);
  294                                             AST.SetChild(astProc, 0,
  295                                               AST.MakeLeaf(AST.NkIdent, pn));
  296                                             AstAppend(AST.NkDeclSeq,
  297                                               astSeq, astTail, astProc);
  298                                             Lower.NoteProcNode(astProc);
  299                                             Lower.ScopeLeave;
  300                                             SymTab.CloseProc;
  301                                             QbeGen.AbortFunc; .) }
  302                                          (. astUnit := AST.MakeNode(AST.NkUnit);
  303                                             AST.SetChild(astUnit, 0,
  304                                               AST.MakeLeaf(AST.NkIdent, m1));
  305                                             AST.SetChild(astUnit, 1, astSeq);
  306                                             AST.SetChild(astUnit, 3, astImp);
  307                                             astDecl := AST.NoNode;
  308                                             astStmt := AST.NoNode; .)
  309        "END"
  310        GetIdent<m2>                      (. IF NOT SymTab.Equal(m1, m2) THEN
  311                                               SemError(202) END;
  312                                             SymTab.EndUnit; .) .
  313    ImplUnit                              (. VAR m1, m2: SymTab.Name;
  314                                               k: CARDINAL;
  315                                               fname: SymTab.Name;
  316                                               unres: BOOLEAN;
  317                                               astNode: AST.Node; .)
  318      = "IMPLEMENTATION" "MODULE"
  319        GetIdent<m1> (. IF NOT SymTab.BeginImpl(m1) THEN
  320                                               SemError(201) END;
  321                                             astStmt := AST.NoNode;
  322                                             astDecl := AST.NoNode;
  323                                             astImp := AST.NoNode;
  324                                             astImpTail := AST.NoNode;
  325                                             nPendVar := 0;
  326                                             QbeGen.SetModule(m1); .)
  327        ";"
  328        { Import                        (. AstAppend(AST.NkDeclSeq,
  329                                               astImp, astImpTail, astDecl); .) }
  330        DeclSeq                           (. astStmt := AST.NoNode; .)
  331        [ "BEGIN"                         (. FlushPend;
  332                                             k := 0;
  333                                             WHILE k < SymTab.FwdPending() DO
  334                                               SymTab.FwdInfo(k, fname, unres);
  335                                               IF unres THEN SemError(201) END;
  336                                               INC(k)
  337                                             END;
  338                                             SymTab.FwdClear;
  339                                             FwdVarFlush;
  340                                             QbeGen.BeginInit(m1); .)
  341          [ StatSeq ]                       (. QbeGen.EndInit; .) ]
  342        "END"
  343        GetIdent<m2>                      (. FlushPend;
  344                                             k := 0;
  345                                             WHILE k < SymTab.FwdPending() DO
  346                                               SymTab.FwdInfo(k, fname, unres);
  347                                               IF unres THEN SemError(201) END;
  348                                               INC(k)
  349                                             END;
  350                                             SymTab.FwdClear;
  351                                             FwdVarFlush;
  352                                             astNode := AST.MakeNode(AST.NkUnit);
  353                                             AST.SetChild(astNode, 0,
  354                                               AST.MakeLeaf(AST.NkIdent, m1));
  355                                             AST.SetChild(astNode, 1, astDecl);
  356                                             AST.SetChild(astNode, 2, astStmt);
  357                                             AST.SetChild(astNode, 3, astImp);
  358                                             astUnit := astNode;
  359                                             IF NOT SymTab.Equal(m1, m2) THEN
  360                                               SemError(202) END;
  361                                             SymTab.EndUnit; .) .
  362    ProgModule                            (. VAR m1, m2: SymTab.Name;
  363                                               k: CARDINAL;
  364                                               fname: SymTab.Name;
  365                                               unres: BOOLEAN;
  366                                               astNode: AST.Node; .)
  367      = "MODULE"
  368        GetIdent<m1> (. IF NOT SymTab.BeginProg(m1) THEN
  369                                               SemError(200) END;
  370                                             astStmt := AST.NoNode;
  371                                             astDecl := AST.NoNode;
  372                                             astImp := AST.NoNode;
  373                                             astImpTail := AST.NoNode;
  374                                             nPendVar := 0;
  375                                             QbeGen.SetModule(m1); .)
  376        [ Priority ]
  377        ";"
  378        { Import                        (. AstAppend(AST.NkDeclSeq,
  379                                               astImp, astImpTail, astDecl); .) }
  380        DeclSeq                           (. astStmt := AST.NoNode; .)
  381        [ "BEGIN"                         (. FlushPend;
  382                                             k := 0;
  383                                             WHILE k < SymTab.FwdPending() DO
  384                                               SymTab.FwdInfo(k, fname, unres);
  385                                               IF unres THEN SemError(201) END;
  386                                               INC(k)
  387                                             END;
  388                                             SymTab.FwdClear;
  389                                             FwdVarFlush;
  390                                             QbeGen.BeginBody; .)
  391          [ StatSeq ] ]
  392        "END"
  393        GetIdent<m2>                      (. FlushPend;
  394                                             k := 0;
  395                                             WHILE k < SymTab.FwdPending() DO
  396                                               SymTab.FwdInfo(k, fname, unres);
  397                                               IF unres THEN SemError(201) END;
  398                                               INC(k)
  399                                             END;
  400                                             SymTab.FwdClear;
  401                                             FwdVarFlush;
  402                                             IF NOT SymTab.Equal(m1, m2) THEN
  403                                               SemError(202) END;
  404                                             astNode := AST.MakeNode(AST.NkUnit);
  405                                             AST.SetChild(astNode, 0,
  406                                               AST.MakeLeaf(AST.NkIdent, m1));
  407                                             AST.SetChild(astNode, 1, astDecl);
  408                                             AST.SetChild(astNode, 2, astStmt);
  409                                             AST.SetChild(astNode, 3, astImp);
  410                                             astUnit := astNode;
  411                                             QbeGen.EndModule(m1);
  412                                             SymTab.EndUnit; .) .
  413    DeclSeq                               (. VAR astSeq, astTail: AST.Node; .)
  414      =                                   (. astSeq := AST.NoNode;
  415                                             astTail := AST.NoNode; .)
  416        { (. astDecl := AST.NoNode; .)
  417          ( ConstBlock | TypeBlock<FALSE> | VarBlock | ProcDecl ";"
  418          | NestedModule ";" | ClassItem ";" )
  419                                          (. AstAppend(AST.NkDeclSeq,
  420                                               astSeq, astTail, astDecl); .) }
  421                                          (. astDecl := astSeq; .) .
  422    (* Local module, Wirth form. Declarations lower like top-level ones
  423       (same QBE module prefix); a BEGIN body becomes an init function
  424       that main calls; the EXPORT list is hoisted into the enclosing
  425       scope at END. *)
  426    NestedModule                          (. VAR m1, m2: SymTab.Name;
  427                                               expNames: ARRAY [0 .. 63] OF SymTab.Name;
  428                                               expCount, k: CARDINAL;
  429                                               astNode, nImp, nImpTail:
  430                                                 AST.Node; .)
  431      = "MODULE"
  432        GetIdent<m1>                      (. IF NOT SymTab.Enter(m1,
  433                                               SymTab.KindModule) THEN
  434                                               SemError(200) END;
  435                                             SymTab.PushScope;
  436                                             expCount := 0;
  437                                             astNode := AST.MakeNode(AST.NkUnit);
  438                                             AST.SetChild(astNode, 0,
  439                                               AST.MakeLeaf(AST.NkIdent, m1));
  440                                             astStmt := AST.NoNode;
  441                                             astDecl := AST.NoNode;
  442                                             nImp := AST.NoNode;
  443                                             nImpTail := AST.NoNode; .)
  444        [ Priority ]
  445        ";"
  446        { Import                        (. AstAppend(AST.NkDeclSeq,
  447                                               nImp, nImpTail, astDecl); .) }
  448        [ "EXPORT" [ "QUALIFIED" ]
  449          GetIdent<expNames[expCount]>    (. INC(expCount); .)
  450          { "," GetIdent<expNames[expCount]>
  451                                          (. INC(expCount); .) }
  452          ";" ]
  453        DeclSeq                           (. astStmt := AST.NoNode; .)
  454        [ "BEGIN"                         (. astStmt := AST.NoNode;
  455                                             QbeGen.BeginInit(m1); .)
  456          [ StatSeq ]                     (. QbeGen.EndInit; .) ]
  457        "END"
  458        GetIdent<m2>                      (. AST.SetChild(astNode, 1, astDecl);
  459                                             AST.SetChild(astNode, 2, astStmt);
  460                                             AST.SetChild(astNode, 3, nImp);
  461                                             astDecl := astNode;
  462                                             IF NOT SymTab.Equal(m1, m2) THEN
  463                                               SemError(202) END;
  464                                             k := 0;
  465                                             WHILE k < expCount DO
  466                                               SymTab.ExportUp(expNames[k]);
  467                                               INC(k)
  468                                             END;
  469                                             SymTab.PopScope; .) .
  470    Priority
  471      = "[" integer "]"                   (. SemError(230); .) .
  472    (* Imports (4.3): FROM materializes the names (unqualified use);
  473       plain IMPORT only demands the module exists — qualified `L.x`
  474       materializes on first use (Design). *)
  475    (* Unknown modules stay unchecked stubs (legacy, so hand-written
  476       import lines don't fail); a known module's missing export is
  477       201. *)
  478    Import                                (. VAR n: SymTab.Name;
  479                                               astImport: AST.Node; .)
  480      = "FROM"
  481        GetIdent<n>                       (. astImport := AST.MakeNode(AST.NkImport);
  482                                             AST.SetChild(astImport, 0,
  483                                               AST.MakeLeaf(AST.NkIdent, n)); .)
  484        "IMPORT"
  485        ImpList<n, astImport> ";"         (. astDecl := astImport; .)
  486      | "IMPORT"                          (. astImport := AST.MakeNode(AST.NkImport); .)
  487        ImpModList<astImport> ";"         (. astDecl := astImport; .) .
  488    ImpList<mod: SymTab.Name; node: AST.Node>
  489                                          (. VAR n: SymTab.Name; .)
  490      = ImpName<mod, node>
  491        { "," ImpName<mod, node> } .
  492    (* Pervasive built-ins imported from SYSTEM (e.g. TSIZE) are
  493       accepted and ignored: the built-in applies regardless. *)
  494    ImpName<mod: SymTab.Name; node: AST.Node>
  495                                          (. VAR n: SymTab.Name; .)
  496      = GetIdent<n> (. AST.SetChild(node, AST.NChild(node),
  497                                               AST.MakeLeaf(AST.NkIdent, n));
  498                                             IF SymTab.Equal(mod, "libc") THEN
  499                                               (* intrinsic C library:
  500                                                  permissive external *)
  501                                               IF NOT SymTab.DeclareCProc(n) THEN
  502                                                 SemError(201) END
  503                                             ELSIF SymTab.ModKnown(mod)
  504                                               AND NOT SymTab.ImportFrom(mod, n) THEN
  505                                               SemError(201) END; .)
  506      | ( "TSIZE" | "SIZE" | "ADR" | "HIGH" | "LEN"
  507        | "CHR" | "ORD" | "ORDL" | "VAL" | "ABS" | "CAP"
  508        | "UCHR" | "CHR8" | "UORD"
  509        | "INC" | "DEC" ) .
  510    ImpModList<node: AST.Node>            (. VAR n: SymTab.Name; .)
  511      = GetIdent<n>                       (. AST.SetChild(node, AST.NChild(node),
  512                                               AST.MakeLeaf(AST.NkIdent, n)); .)
  513        { "," GetIdent<n>                 (. AST.SetChild(node, AST.NChild(node),
  514                                               AST.MakeLeaf(AST.NkIdent, n)); .) } .
  515    (* Opaque TYPE declarations (definition modules). The targetless
  516       alias resolves to InvalidType until step 4 completes it. *)
  517    (* Scalar-phase TYPEs: named types, integer subranges, enumerations.
  518       Opaque "TYPE T;" needs isDef (definition units); elsewhere 231.
  519       Composite forms (ARRAY/RECORD/SET/POINTER) arrive with step 3. *)
  520    TypeBlock<isDef: BOOLEAN>             (. VAR astSeq, astTail: AST.Node; .)
  521      = "TYPE"                            (. SymTab.BeginTypeBlock;
  522                                             astSeq := AST.NoNode;
  523                                             astTail := AST.NoNode; .)
  524        { (. astDecl := AST.NoNode; .)
  525          ( TypeItem<isDef> ";" | ClassItem ";" )
  526                                          (. AstAppend(AST.NkDeclSeq,
  527                                               astSeq, astTail, astDecl); .) }
  528                                          (. SymTab.EndTypeBlock;
  529                                             astDecl := astSeq; .) .
  530    TypeItem<isDef: BOOLEAN>              (. VAR n: SymTab.Name;
  531                                               t, op: SymTab.TypeIndex;
  532                                               astNode: AST.Node; .)
  533      = GetIdent<n>                       (. op := SymTab.OpaqueBase(n);
  534                                             IF op = SymTab.InvalidType THEN
  535                                               IF NOT SymTab.Enter(n,
  536                                                  SymTab.KindType) THEN
  537                                                 SemError(200) END
  538                                             END; .)
  539        ( "=" Type<t, FALSE> (. astNode := AST.MakeNode(AST.NkTypeDecl);
  540                                               AST.SetChild(astNode, 0,
  541                                                 AST.MakeLeaf(AST.NkIdent, n));
  542                                               AST.SetTy(astNode, t);
  543                                               astDecl := astNode;
  544                                               IF op # SymTab.InvalidType THEN
  545                                               SymTab.SetTarget(op, t)
  546                                             ELSE SymTab.SetSymType(n, t)
  547                                             END; .)
  548        |                                 (. IF op # SymTab.InvalidType THEN
  549                                               (* stays opaque *)
  550                                             ELSIF NOT isDef THEN
  551                                               SemError(231)
  552                                             ELSE SymTab.SetSymType(n,
  553                                               SymTab.NewAlias()) END; .) ) .
  554    Type<VAR t: SymTab.TypeIndex; allowOpen: BOOLEAN>
  555      = TypeIdent<t> [ Subrange<t> ]     (* anchored subrange: T[lo..hi] *)
  556      | Subrange<t>
  557      | Enum<t>
  558      | ArrayType<t, allowOpen>
  559      | SetType<t>
  560      | RecordType<t>
  561      | PointerType<t>
  562      | ProcType<t> .
  563    PointerType<VAR t: SymTab.TypeIndex>  (. VAR base: SymTab.TypeIndex; .)
  564      = "POINTER" "TO" Type<base, FALSE>(. t := SymTab.NewPtr(base); .) .
  565    (* Procedure types (step 8.5): PROCEDURE (params): result. Values
  566       are code pointers; params are collected into the descriptor. *)
  567    ProcType<VAR t: SymTab.TypeIndex>     (. VAR res, pt: SymTab.TypeIndex;
  568                                               isV: BOOLEAN; .)
  569      = "PROCEDURE"                       (. res := SymTab.InvalidType;
  570                                             t := SymTab.NewProcType(res); .)
  571        [ "(" [ ProcTypeSection<t> { ";" ProcTypeSection<t> } ] ")" ]
  572        [ ":" TypeIdent<res>              (. SymTab.SetProcTypeRes(t, res); .) ] .
  573    ProcTypeSection<t: SymTab.TypeIndex>  (. VAR pt: SymTab.TypeIndex;
  574                                               isV: BOOLEAN;
  575                                               cnt, k: CARDINAL;
  576                                               names: ARRAY [0 .. 15] OF SymTab.Name; .)
  577      =                                   (. isV := FALSE; cnt := 0; .)
  578        [ "VAR"                           (. isV := TRUE; .) ]
  579        ( GetIdent<names[cnt]>            (. INC(cnt); .)
  580          { "," GetIdent<names[cnt]>      (. INC(cnt); .) }
  581          ( ":" Type<pt, TRUE>           (. k := 0;
  582                                             WHILE k < cnt DO
  583                                               SymTab.ProcTypeAdd(t, isV, pt);
  584                                               INC(k)
  585                                             END; .)
  586          |                               (. (* type-only parameter list:
  587                                                each name is a type (GNU
  588                                                shorthand used by the
  589                                                Coco/R scanner frame) *)
  590                                             k := 0;
  591                                             WHILE k < cnt DO
  592                                               IF SymTab.Lookup(names[k])
  593                                                  AND ((SymTab.SymKind(names[k]) = SymTab.KindType)
  594    OR (SymTab.SymKind(names[k]) = SymTab.KindPredef)) THEN
  595                                                 pt := SymTab.SymType(names[k])
  596                                               ELSE SemError(201);
  597                                                 pt := SymTab.InvalidType
  598                                               END;
  599                                               SymTab.ProcTypeAdd(t, isV, pt);
  600                                               INC(k)
  601                                             END; .) )
  602        | Type<pt, TRUE>                 (. (* unnamed parameter (PIM):
  603                                                e.g. PROCEDURE (VAR ARRAY OF REAL) *)
  604                                             SymTab.ProcTypeAdd(t, isV, pt); .) ) .
  605    (* Arrays: "OF" without bounds is an open formal (allowed only
  606       where allowOpen); "[lo..hi, ...]" nests bounded levels inside
  607       out. Bounds are folded literals (int/char); anything else 230.
  608       Bare-type indices ("ARRAY Color OF") wait for enum ordinals. *)
  609    ArrayType<VAR t: SymTab.TypeIndex; allowOpen: BOOLEAN>
  610                                          (. VAR elem: SymTab.TypeIndex;
  611                                               ok: BOOLEAN;
  612                                               bnds, bndh: ARRAY [0 .. 7] OF INTEGER;
  613                                               nb, k: CARDINAL;
  614                                               idx: SymTab.TypeIndex;
  615                                               ilo, ihi: INTEGER; .)
  616      = "ARRAY"
  617        ( "OF" Type<elem, FALSE>          (. IF NOT allowOpen THEN
  618                                               SemError(230) END;
  619                                             t := SymTab.NewOpenArray(elem); .)
  620        | TypeIdent<idx> [ Subrange<idx> ]
  621          "OF" Type<elem, FALSE>          (. (* index-type array: the index
  622                                                type's ordinal bounds give the
  623                                                [lo..hi] pair *)
  624                                             IF SymTab.TypeBounds(idx, ilo,
  625                                                ihi)
  626                                             THEN t := SymTab.NewArrayB(elem,
  627                                                    ilo, ihi)
  628                                             ELSE SemError(230);
  629                                               t := SymTab.InvalidType
  630                                             END; .)
  631        | "["                             (. SymTab.BoundBegin; ok := TRUE; .)
  632          BoundPair<ok>
  633          { "," BoundPair<ok> }
  634          "]"                             (. (* snapshot before the element
  635                                                type, which reuses the bound
  636                                                buffer for a nested ARRAY *)
  637                                             nb := SymTab.BoundCount();
  638                                             k := 0;
  639                                             WHILE k < nb DO
  640                                               bnds[k] := SymTab.BoundLo(k);
  641                                               bndh[k] := SymTab.BoundHi(k);
  642                                               INC(k)
  643                                             END; .)
  644          "OF" Type<elem, FALSE>
  645                                          (. IF ok THEN
  646                                               k := nb;
  647                                               WHILE k > 0 DO
  648                                                 DEC(k);
  649                                                 elem := SymTab.NewArrayB(
  650                                                   elem, bnds[k], bndh[k])
  651                                               END;
  652                                               t := elem
  653                                             ELSE t := SymTab.InvalidType
  654                                             END; .) ) .
  655    BoundPair<VAR ok: BOOLEAN>            (. VAR tlo, thi: SymTab.TypeIndex;
  656                                               qlo, qhi: QbeGen.QVal;
  657                                               lo, hi: INTEGER;
  658                                               cl, cl2: INTEGER; .)
  659      = Expr<tlo, qlo> ".." Expr<thi, qhi>
  660                                          (. IF (tlo = SymTab.InvalidType)
  661                                              OR (thi = SymTab.InvalidType) THEN
  662                                             ok := FALSE
  663                                           ELSE cl := SymTab.ClassOf(tlo);
  664                                             cl2 := SymTab.ClassOf(thi);
  665                                             IF ((cl # SymTab.ClInt)
  666   AND (cl # SymTab.ClChar))
  667                                                OR ((cl2 # SymTab.ClInt)
  668   AND (cl2 # SymTab.ClChar)) THEN
  669                                               SemError(230); ok := FALSE
  670                                             ELSIF NOT SymTab.ConstInt(qlo, lo)
  671                                                OR NOT SymTab.ConstInt(qhi, hi)
  672                                                OR (lo > hi) THEN
  673                                               SemError(230); ok := FALSE
  674                                              ELSIF NOT SymTab.BoundAdd(lo, hi) THEN
  675                                                SemError(230); ok := FALSE
  676                                              END;
  677                                            END; .) .
  678    (* Sets: multi-word masks over bases ≤ 256 values (bool, char,
  679       bounded subranges; enums wait for ordinals, INTEGER is
  680       unbounded). Literals are SET OF [0..255]; assignment and
  681       comparison across suitable bases are lenient (masks over min
  682       words + zero-check extras), out-of-span literals are 222. *)
  683    SetType<VAR t: SymTab.TypeIndex>      (. VAR base: SymTab.TypeIndex;
  684                                               blo, bhi, bspan: INTEGER;
  685                                               bcls: INTEGER; .)
  686      = "SET" "OF" Type<base, FALSE>
  687                                          (. IF base = SymTab.InvalidType THEN
  688                                               t := SymTab.InvalidType
  689                                             ELSE bcls :=
  690                                                    SymTab.ClassOf(base);
  691                                               IF bcls = SymTab.ClBool THEN
  692                                                 blo := 0; bspan := 2
  693                                               ELSIF bcls = SymTab.ClChar THEN
  694                                                 blo := 0; bspan := 256
  695                                               ELSIF bcls = SymTab.ClEnum THEN
  696                                                 blo := 0;
  697                                                 bspan := VAL(INTEGER,
  698                                                   SymTab.EnumCount(base))
  699                                               ELSIF SymTab.SubBounds(base,
  700                                                       blo, bhi) THEN
  701                                                 bspan := bhi - blo + 1
  702                                               ELSE bspan := 0 END;
  703                                               IF (bspan <= 0)
  704                                                  OR (bspan > 65536) THEN
  705                                                 SemError(230);
  706                                                 t := SymTab.InvalidType
  707                                               ELSE t := SymTab.NewSet(base)
  708                                               END
  709                                             END; .) .
  710    (* Records: flat blobs; array fields are pointers to static
  711       descriptors (locked amendment), nested records inline. Field
  712       offsets static and declaration-ordered. *)
  713    (* Field list: plain fields and (optionally) one variant part.  The
  714       variant part is a `CASE ... END` item; because it starts with the
  715       CASE keyword it is unambiguously distinguishable from a field
  716       (which starts with an identifier). *)
  717    RecordType<VAR t: SymTab.TypeIndex>   (. VAR t2: SymTab.TypeIndex;
  718                                               tagOk: BOOLEAN; .)
  719      = "RECORD"                          (. t := SymTab.NewRecord(); .)
  720        [ RecItem<t> { ";" [ RecItem<t> ] } ]
  721        "END" .
  722    RecItem<rec: SymTab.TypeIndex>        (. VAR tt: SymTab.TypeIndex; .)
  723      = RecField<rec>
  724      | CaseField<rec>                    (. SymTab.MarkVariant(rec); .) .
  725    (* A variant part: CASE tag : Type OF variants.  The layout overlays
  726       every branch from the tag slot (see SymTab.ComputeOffsets). *)
  727    CaseField<rec: SymTab.TypeIndex>      (. VAR tagT: SymTab.TypeIndex;
  728                                               tagN: SymTab.Name; .)
  729      = "CASE"                            (. SymTab.ResetFields(rec); .)
  730        GetIdent<tagN>                    (. IF NOT SymTab.FieldPending(rec,
  731                                               tagN) THEN
  732                                               SemError(200) END; .)
  733        ":" Type<tagT, FALSE>             (. IF (tagT # SymTab.InvalidType)
  734    AND NOT SymTab.IsOrdinal(tagT) THEN
  735                                               SemError(224)
  736                                             END;
  737                                             SymTab.FixPendingF(rec, tagT);
  738                                             SymTab.SetVariantTag(rec, tagN); .)
  739        "OF"
  740        RecFieldList<rec>
  741        { "|"                             (. SymTab.ResetFields(rec); .)
  742          RecFieldList<rec> }
  743        "END" .
  744    RecFieldList<rec: SymTab.TypeIndex>   (. VAR lt, lq: SymTab.TypeIndex;
  745                                               lv1, lv2: QbeGen.QVal; .)
  746      = VarLabel<lt, lv1> [ ".." VarLabel<lq, lv2> ] ":"
  747        RecField<rec> { ";" [ RecField<rec> ] } .
  748    (* Variant case label: a constant (or a constant range).  Values are
  749       not interpreted (the layout overlays regardless). *)
  750    VarLabel<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal>
  751                                          (. VAR lname: SymTab.Name; .)
  752      = ( ident                         (. LexName(lname);
  753                                             QbeGen.CopyOp("0", q);
  754                                             t := SymTab.IntType(); .)
  755        | integer                       (. LexString(lname);
  756                                             QbeGen.CopyOp("0", q);
  757                                             t := SymTab.IntType(); .)
  758        | charConst                     (. LexString(lname);
  759                                             QbeGen.CopyOp("0", q);
  760                                             t := SymTab.CharType(); .) ) .
  761    RecField<rec: SymTab.TypeIndex>       (. VAR n: SymTab.Name;
  762                                               t2: SymTab.TypeIndex; .)
  763      = RecIdents<rec> ":" Type<t2, FALSE>(. SymTab.FixPendingF(rec, t2); .) .
  764    RecIdents<rec: SymTab.TypeIndex>      (. VAR n: SymTab.Name; .)
  765      = GetIdent<n>                       (. IF NOT SymTab.FieldPending(rec,
  766                                               n) THEN
  767                                               SemError(200) END; .)
  768        { "," GetIdent<n>                 (. IF NOT SymTab.FieldPending(rec,
  769                                               n) THEN
  770                                               SemError(200) END; .) } .
  771    TypeIdent<VAR t: SymTab.TypeIndex>    (. VAR n, qid: SymTab.Name;
  772                                               k: INTEGER;
  773                                               dotted: BOOLEAN; .)
  774      = GetIdent<n>                       (. dotted := FALSE;
  775                                             IF NOT SymTab.Lookup(n) THEN
  776                                               k := -1;
  777                                               t := SymTab.ForwardType(n);
  778                                               IF t = SymTab.InvalidType THEN
  779                                                 SemError(201)
  780                                               END
  781                                             ELSE k := SymTab.SymKind(n);
  782                                               IF (k = SymTab.KindType)
  783                                                  OR (k = SymTab.KindPredef) THEN
  784                                                 t := SymTab.SymType(n)
  785                                               ELSE t := SymTab.InvalidType
  786                                               END
  787                                             END; .)
  788        [ "." GetIdent<qid>               (. dotted := TRUE;
  789                                             IF k = SymTab.KindModule THEN
  790                                               t := SymTab.QualType(n, qid);
  791                                               IF t = SymTab.InvalidType THEN
  792                                                 SemError(201)
  793                                               END
  794                                             ELSE SemError(221);
  795                                               t := SymTab.InvalidType
  796                                             END; .) ]
  797                                          (. IF NOT dotted THEN
  798                                               IF (k = SymTab.KindModule)
  799                                                  OR ((k # SymTab.KindType)
  800    AND (k # SymTab.KindPredef)
  801    AND (k # SymTab.KindImport)
  802    AND (k # -1)) THEN
  803                                                 SemError(221)
  804                                               END
  805                                             END; .) .
  806    Subrange<VAR t: SymTab.TypeIndex>     (. VAR tlo, thi: SymTab.TypeIndex;
  807                                               qlo, qhi: QbeGen.QVal;
  808                                               lo, hi: INTEGER; .)
  809      = "[" Expr<tlo, qlo> ".." Expr<thi, qhi>
  810                                          (. IF (tlo = SymTab.InvalidType)
  811                                              OR (thi = SymTab.InvalidType) THEN
  812                                             t := SymTab.InvalidType
  813                                           ELSIF NOT SymTab.IsOrdinal(tlo)
  814                                              OR NOT SymTab.IsOrdinal(thi) THEN
  815                                             SemError(230);
  816                                             t := SymTab.InvalidType
  817                                           ELSIF NOT SymTab.ConstInt(qlo, lo)
  818                                              OR NOT SymTab.ConstInt(qhi, hi)
  819                                              OR (lo > hi) THEN
  820                                             SemError(230);
  821                                             t := SymTab.InvalidType
  822                                           ELSE t := SymTab.NewSubR(lo, hi)
  823                                           END; .)
  824        "]" .
  825    Enum<VAR t: SymTab.TypeIndex>         (. VAR n: SymTab.Name;
  826                                               ord: INTEGER;
  827                                               qv: QbeGen.QVal; .)
  828      = "("                               (. t := SymTab.NewEnum();
  829                                             ord := 0; .)
  830        GetIdent<n>                       (. IF NOT SymTab.Enter(n,
  831                                               SymTab.KindConst) THEN
  832                                               SemError(200) END;
  833                                             SymTab.SetSymType(n, t);
  834                                             QbeGen.IntStr(ord, qv);
  835                                             SymTab.SetSymVal(n, qv);
  836                                             Lower.NoteVar(n,
  837                                               SymTab.KindConst, t);
  838                                             Lower.NoteConstVal(qv);
  839                                             INC(ord); .)
  840        { "," GetIdent<n>                 (. IF NOT SymTab.Enter(n,
  841                                               SymTab.KindConst) THEN
  842                                               SemError(200) END;
  843                                             SymTab.SetSymType(n, t);
  844                                             QbeGen.IntStr(ord, qv);
  845                                             SymTab.SetSymVal(n, qv);
  846                                             Lower.NoteVar(n,
  847                                               SymTab.KindConst, t);
  848                                             Lower.NoteConstVal(qv);
  849                                             INC(ord); .) }
  850        ")"                               (. SymTab.SetEnumCount(t,
  851                                               VAL(CARDINAL, ord)); .) .
  852    (* Clarion-form classes (docs/OOP.txt): declaration + single
  853       inheritance + IMPLEMENTATION blocks. Scopes and member checks
  854       now; lowering (vtable, dispatch, THIS) later — one 230 per
  855       class/impl block. Methods end with ";" per the Table example
  856       (not "," as in the sketch). No underscores in identifiers. *)
  857    (* Single CLASS item in both loops: separating declaration from
  858       IMPLEMENTATION at the loop level needs 2-token lookahead
  859       (CLASS ident vs CLASS IMPLEMENTATION), which LL(1) cannot do.
  860       The second token decides after CLASS is consumed. A misplaced
  861       CLASS IMPLEMENTATION inside TYPE still parses (harmless: the
  862       whole unit ends 230 until lowering). *)
  863    ClassItem
  864      = "CLASS" ( "IMPLEMENTATION" ClassImplRest | ClassRest ) .
  865    ClassRest                             (. VAR cn, m2, pn: SymTab.Name;
  866                                               ct: SymTab.TypeIndex; .)
  867      = GetIdent<cn>                      (. IF NOT SymTab.Enter(cn,
  868                                               SymTab.KindType) THEN
  869                                               SemError(200) END;
  870                                             ct := SymTab.NewClass();
  871                                             SymTab.SetSymType(cn, ct);
  872                                             SymTab.PushClassScope(ct);
  873                                             astCls := AST.MakeNode(AST.NkClassDecl);
  874                                             AST.SetChild(astCls, 0,
  875                                               AST.MakeLeaf(AST.NkIdent, cn));
  876                                             astClsP := AST.NoNode;
  877                                             astClsPTail := AST.NoNode;
  878                                             astClsF := AST.NoNode;
  879                                             astClsFTail := AST.NoNode;
  880                                             astClsM := AST.NoNode;
  881                                             astClsMTail := AST.NoNode; .)
  882        [ Parents<ct> ]
  883        ";"
  884        { ClassField<ct> ";" }
  885        { MethodHeading<pn, SymTab.InvalidType> ";"
  886                                          (. Lower.ScopeLeave;
  887                                             SymTab.CloseProc;
  888                                             QbeGen.AbortFunc; .) }
  889        "END"
  890        GetIdent<m2>                      (. IF NOT SymTab.Equal(cn, m2) THEN
  891                                               SemError(202) END;
  892                                             SymTab.LayoutClass(ct);
  893                                             SymTab.PopScope;
  894                                             AST.SetChild(astCls, 1, astClsP);
  895                                             AST.SetChild(astCls, 2, astClsF);
  896                                             AST.SetChild(astCls, 3, astClsM);
  897                                             astDecl := astCls; .) .
  898    Parents<ct: SymTab.TypeIndex>         (. VAR p: SymTab.Name; .)
  899      = "(" Parent1<ct>
  900        { "," GetIdent<p>                 (. SemError(230); .) }
  901        ")" .
  902    Parent1<ct: SymTab.TypeIndex>         (. VAR p: SymTab.Name;
  903                                               pt: SymTab.TypeIndex; .)
  904      = GetIdent<p>                       (. IF NOT SymTab.Lookup(p) THEN
  905                                               SemError(201)
  906                                             ELSE pt := SymTab.SymType(p);
  907                                               IF SymTab.ClassOf(pt) #
  908                                                  SymTab.ClClass THEN
  909                                                 SemError(230)
  910                                               ELSE SymTab.SetParent(ct, pt)
  911                                               END
  912                                             END;
  913                                             AstAppend(AST.NkFieldDecl,
  914                                               astClsP, astClsPTail,
  915                                               AST.MakeLeaf(AST.NkIdent, p)); .) .
  916    ClassField<ct: SymTab.TypeIndex>      (. VAR n, rhs: SymTab.Name;
  917                                               t: SymTab.TypeIndex;
  918                                               astNode: AST.Node; .)
  919      = GetIdent<n>
  920        ( "=" GetIdent<rhs>               (. IF NOT SymTab.Enter(n,
  921                                               SymTab.KindConst) THEN
  922                                               SemError(200) END;
  923                                             astNode := AST.MakeNode(AST.NkConstDecl);
  924                                             AST.SetChild(astNode, 0,
  925                                               AST.MakeLeaf(AST.NkIdent, n));
  926                                             AST.SetChild(astNode, 1,
  927                                               AST.MakeLeaf(AST.NkIdent, rhs));
  928                                             AstAppend(AST.NkFieldDecl,
  929                                               astClsF, astClsFTail, astNode);
  930                                             IF SymTab.Lookup(rhs) THEN
  931                                               SymTab.SetSymType(n,
  932                                                 SymTab.SymType(rhs))
  933                                             END; .)
  934        |                                 (. IF NOT SymTab.FieldPending(ct,
  935                                               n) THEN
  936                                               SemError(200) END;
  937                                             astNode := AST.MakeNode(AST.NkVarDecl);
  938                                             AST.SetChild(astNode, 0,
  939                                               AST.MakeLeaf(AST.NkIdent, n)); .)
  940          { "," GetIdent<n>               (. IF NOT SymTab.FieldPending(ct,
  941                                               n) THEN
  942                                               SemError(200) END;
  943                                             AST.SetChild(astNode,
  944                                               AST.NChild(astNode),
  945                                               AST.MakeLeaf(AST.NkIdent, n)); .) }
  946          ":" Type<t, FALSE>              (. SymTab.FixPendingF(ct, t);
  947                                             AST.SetTy(astNode, t);
  948                                             AstAppend(AST.NkFieldDecl,
  949                                               astClsF, astClsFTail, astNode); .) ) .
  950    MethodHeading<VAR pn: SymTab.Name; ct: SymTab.TypeIndex>
  951                                          (. VAR wantVirt: BOOLEAN; .)
  952      =                                   (. wantVirt := FALSE; .)
  953        [ "VIRTUAL"                       (. wantVirt := TRUE; .) ]
  954        ProcHeading<pn, ct>               (. IF wantVirt THEN
  955                                               SymTab.MarkVirtual END;
  956                                             astMethod := AST.MakeNode(AST.NkProcDecl);
  957                                             AST.SetChild(astMethod, 0,
  958                                               AST.MakeLeaf(AST.NkIdent, pn));
  959                                             IF wantVirt THEN
  960                                               AST.SetOp(astMethod, 3)
  961                                             ELSE AST.SetOp(astMethod, 0)
  962                                             END;
  963                                             AstAppend(AST.NkFieldDecl,
  964                                               astClsM, astClsMTail, astMethod); .) .
  965    ClassImplRest                         (. VAR cn, m2: SymTab.Name;
  966                                               ct: SymTab.TypeIndex; .)
  967      = GetIdent<cn>                      (. IF NOT SymTab.Lookup(cn) THEN
  968                                               SemError(201);
  969                                               ct := SymTab.InvalidType
  970                                             ELSE ct := SymTab.SymType(cn);
  971                                               IF SymTab.ClassOf(ct) #
  972                                                  SymTab.ClClass THEN
  973                                                 SemError(230);
  974                                                 ct := SymTab.InvalidType
  975                                               END
  976                                             END;
  977                                             astCls := AST.MakeNode(AST.NkClassDecl);
  978                                             AST.SetOp(astCls, 1);
  979                                             AST.SetChild(astCls, 0,
  980                                               AST.MakeLeaf(AST.NkIdent, cn));
  981                                             astClsM := AST.NoNode;
  982                                             astClsMTail := AST.NoNode;
  983                                             astStmt := AST.NoNode;
  984                                             IF ct #
  985                                                SymTab.InvalidType THEN
  986                                               IF NOT SymTab.PushClassMembers(
  987                                                      ct) THEN
  988                                                 SemError(230) END;
  989                                               SymTab.PushImplClass(ct)
  990                                             END; .)
  991        ";" { MethodImpl<ct> ";" }
  992                                          (. astStmt := AST.NoNode; .)
  993        [ "BEGIN"                         (. astStmt := AST.MakeNode(AST.NkBlock);
  994                                             QbeGen.BeginInit(cn); .)
  995          [ StatSeq ]                     (. QbeGen.EndInit; .) ]
  996        "END"
  997        GetIdent<m2>                      (. IF NOT SymTab.Equal(cn, m2) THEN
  998                                               SemError(202) END;
  999                                             SymTab.PopImplClass;
 1000                                             SymTab.PopScope;
 1001                                             AST.SetChild(astCls, 1, AST.NoNode);
 1002                                             AST.SetChild(astCls, 2, astStmt);
 1003                                             AST.SetChild(astCls, 3, astClsM);
 1004                                             astDecl := astCls; .) .
 1005    MethodImpl<ct: SymTab.TypeIndex>      (. VAR pn: SymTab.Name;
 1006                                               thisQ: QbeGen.QVal;
 1007                                               methRes: SymTab.TypeIndex; .)
 1008      = MethodHeading<pn, ct> ";"
 1009                                          (. IF (ct #
 1010                                                SymTab.InvalidType)
 1011   AND NOT SymTab.MethodExists(ct,
 1012                                                    pn) THEN
 1013                                               SemError(201) END; .)
 1014        ( "FORWARD"                       (. AST.SetOp(astMethod, 1);
 1015                                             SymTab.MarkFwd;
 1016                                             QbeGen.AbortFunc;
 1017                                             Lower.ScopeLeave;
 1018                                             SymTab.CloseProc; .)
 1019        |                                 (. QbeGen.EndFuncHeader;
 1020                                             (* bind the receiver: bare
 1021                                                field names resolve
 1022                                                against THIS *)
 1023                                             QbeGen.ThisBase(thisQ);
 1024                                             QbeGen.PushWith(thisQ); .)
 1025          Block<pn>                       (. AST.SetChild(astMethod, 1, astStmt);
 1026                                             QbeGen.PopWith;
 1027                                             methRes := SymTab.CurRes();
 1028                                             Lower.ScopeLeave;
 1029                                             SymTab.CloseProc;
 1030                                             QbeGen.EndFunc(methRes); .) ) .
 1031    ConstBlock                            (. VAR astSeq, astTail: AST.Node; .)
 1032      = "CONST"                           (. astSeq := AST.NoNode;
 1033                                             astTail := AST.NoNode; .)
 1034        { ConstDecl ";"                   (. AstAppend(AST.NkDeclSeq,
 1035                                               astSeq, astTail, astDecl); .) }
 1036                                          (. astDecl := astSeq; .) .
 1037    ConstDecl                             (. VAR n: SymTab.Name;
 1038                                               t: SymTab.TypeIndex;
 1039                                               qv: QbeGen.QVal;
 1040                                               cls: INTEGER;
 1041                                               astNode: AST.Node; .)
 1042      = GetIdent<n>                       (. IF NOT SymTab.Enter(n,
 1043                                               SymTab.KindConst) THEN
 1044                                               SemError(200) END; .)
 1045        "="
 1046        Expr<t, qv> (. astNode := AST.MakeNode(AST.NkConstDecl);
 1047                                             AST.SetChild(astNode, 0,
 1048                                               AST.MakeLeaf(AST.NkIdent, n));
 1049                                             AST.SetChild(astNode, 1, astCur);
 1050                                             AST.SetTy(astNode, t);
 1051                                             astDecl := astNode;
 1052                                             Lower.NoteVar(n, SymTab.KindConst, t);
 1053                                             Lower.NoteConstVal(qv);
 1054                                             SymTab.SetSymType(n, t);
 1055                                             cls := SymTab.ClassOf(t);
 1056                                             IF (cls = SymTab.ClArray)
 1057                                                OR (cls = SymTab.ClRecord)
 1058                                                OR (cls = SymTab.ClClass)
 1059                                                OR (cls = SymTab.ClStr)
 1060                                                OR (cls = SymTab.ClUStr) THEN
 1061                                               (* an aggregate/string
 1062                                                  constant: qv is its
 1063                                                  descriptor address; no
 1064                                                  scalar data *)
 1065                                               SymTab.SetSymVal(n, qv)
 1066                                             ELSIF NOT QbeGen.IsImm(qv) THEN
 1067                                               SemError(230)
 1068                                             ELSE
 1069                                               SymTab.SetSymVal(n, qv);
 1070                                               QbeGen.DeclConst(n, qv, t)
 1071                                             END; .) .
 1072    VarBlock                              (. VAR astSeq, astTail: AST.Node; .)
 1073      = "VAR"                             (. astSeq := AST.NoNode;
 1074                                             astTail := AST.NoNode; .)
 1075        { VarDecl ";"                     (. AstAppend(AST.NkDeclSeq,
 1076                                               astSeq, astTail, astDecl); .) }
 1077                                          (. astDecl := astSeq; .) .
 1078    VarDecl                               (. VAR nm: SymTab.Name;
 1079                                               t: SymTab.TypeIndex;
 1080                                               i: CARDINAL;
 1081                                               cls: INTEGER;
 1082                                               astNode, astTail: AST.Node; .)
 1083      = VarIdents ":"
 1084        Type<t, FALSE> (. astNode := AST.MakeNode(AST.NkVarDecl);
 1085                                             astTail := astNode;
 1086                                             i := 0;
 1087                                             WHILE i < SymTab.PendCount() DO
 1088                                               SymTab.PendName(i, nm);
 1089                                               Lower.NoteVar(nm, SymTab.KindVar, t);
 1090                                               (* chunked: a VAR list can
 1091                                                  exceed AST.MaxChild *)
 1092                                               AstAppend(AST.NkBlock,
 1093                                                 astNode, astTail,
 1094                                                 AST.MakeLeaf(AST.NkIdent, nm));
 1095                                               INC(i)
 1096                                             END;
 1097                                             AST.SetTy(astNode, t);
 1098                                             astDecl := astNode;
 1099                                             cls := SymTab.ClassOf(t);
 1100                                             IF (t # SymTab.InvalidType)
 1101   AND NOT SymTab.IsUnresolved(t)
 1102   AND (cls # SymTab.ClInt)
 1103   AND (cls # SymTab.ClBool)
 1104   AND (cls # SymTab.ClChar)
 1105   AND (cls # SymTab.ClReal)
 1106   AND (cls # SymTab.ClArray)
 1107   AND (cls # SymTab.ClSet)
 1108   AND (cls # SymTab.ClRecord)
 1109   AND (cls # SymTab.ClPtr)
 1110   AND (cls # SymTab.ClLong)
 1111   AND (cls # SymTab.ClProc)
 1112   AND (cls # SymTab.ClUChar)
 1113   AND (cls # SymTab.ClUStr)
 1114   AND (cls # SymTab.ClEnum)
 1115   AND (cls # SymTab.ClClass) THEN
 1116                                               SemError(230) END;
 1117                                             IF QbeGen.LocFull() THEN
 1118                                               SemError(233) END;
 1119                                             i := 0;
 1120                                             IF SymTab.IsUnresolved(t)
 1121                                                AND NOT SymTab.InProc() THEN
 1122                                               (* a forward-typed global:
 1123                                                  defer emission until the
 1124                                                  TYPE block completes *)
 1125                                               WHILE i < SymTab.PendCount() DO
 1126                                                 SymTab.PendName(i, nm);
 1127                                                 IF nPendVar <=
 1128                                                    HIGH(pendVarName) THEN
 1129                                                   pendVarName[nPendVar] := nm;
 1130                                                   pendVarT[nPendVar] := t;
 1131                                                   INC(nPendVar)
 1132                                                 END;
 1133                                                 INC(i)
 1134                                               END
 1135                                             ELSE
 1136                                               WHILE i < SymTab.PendCount() DO
 1137                                                 SymTab.PendName(i, nm);
 1138                                                 QbeGen.DeclVar(nm, t);
 1139                                                 INC(i)
 1140                                               END
 1141                                             END;
 1142                                             (* a plain VAR list, not a
 1143                                                heading: the signature
 1144                                                result is discarded *)
 1145                                             IF NOT SymTab.FixPending(t) THEN
 1146                                             END; .) .
 1147    VarIdents                             (. VAR n: SymTab.Name; .)
 1148      = GetIdent<n>                       (. IF NOT SymTab.EnterPending(n,
 1149                                               SymTab.KindVar) THEN
 1150                                               SemError(200) END; .)
 1151        { ","
 1152          GetIdent<n>                     (. IF NOT SymTab.EnterPending(n,
 1153                                               SymTab.KindVar) THEN
 1154                                               SemError(200) END; .) } .
 1155    ParIdents<isV: BOOLEAN>               (. VAR n: SymTab.Name; .)
 1156      = GetIdent<n>                       (. IF NOT SymTab.EnterParam(n, isV) THEN
 1157                                               SemError(200) END; .)
 1158        { "," GetIdent<n>                 (. IF NOT SymTab.EnterParam(n, isV) THEN
 1159                                               SemError(200) END; .) } .
 1160    (* Procedure headings enter scopes/params/result and buffer the
 1161       QBE header; bodies lower to functions (4.1, module level only).
 1162       FORWARD marks; the body heading re-enters (signature compare
 1163       deferred). Nested procedures parse + check, lowering = 4.2. *)
 1164    ProcHeading<VAR pn: SymTab.Name; methCls: SymTab.TypeIndex>
 1165                                          (. VAR t: SymTab.TypeIndex;
 1166                                               mg: QbeGen.QVal; .)
 1167      = "PROCEDURE"
 1168        GetIdent<pn>                      (. IF methCls #
 1169                                                SymTab.InvalidType THEN
 1170                                             (* a method: resume the
 1171                                                declared symbol (reuse
 1172                                                its uid) *)
 1173                                             IF NOT SymTab.ResumeMethod(
 1174                                                  methCls, pn) THEN
 1175                                               SemError(200) END
 1176                                             ELSIF NOT SymTab.EnterProc(pn) THEN
 1177                                             IF NOT SymTab.ReenterProc(pn) THEN
 1178                                               IF NOT SymTab.ResumeProc(pn) THEN
 1179                                                 SemError(200) END
 1180                                               END
 1181                                             END;
 1182                                             Lower.ScopeEnter;
 1183                                             Lower.NoteProc(pn,
 1184                                               SymTab.ProcUid(pn),
 1185                                               SymTab.InvalidType,
 1186                                               SymTab.ProcDepthOf(pn),
 1187                                               FALSE);
 1188                                             IF methCls #
 1189                                                SymTab.InvalidType THEN
 1190                                               QbeGen.Mangled(pn,
 1191                                                 SymTab.MethUid(), mg)
 1192                                             ELSE
 1193                                               QbeGen.Mangled(pn,
 1194                                                 SymTab.ProcUid(pn), mg)
 1195                                             END;
 1196                                             QbeGen.BeginFunc(mg);
 1197                                             IF methCls #
 1198                                                SymTab.InvalidType THEN
 1199                                               (* hidden THIS receiver:
 1200                                                  a VAR param of the
 1201                                                  class type, pushed as
 1202                                                  the WITH base *)
 1203                                               IF NOT SymTab.EnterThisParam(
 1204                                                    methCls) THEN
 1205                                                 SemError(200) END;
 1206                                               IF NOT QbeGen.FuncParam(
 1207                                                    "THIS", TRUE,
 1208                                                    methCls) THEN
 1209                                                 SemError(233) END
 1210                                             END; .)
 1211        [ FormalParams ]
 1212        [ ":" TypeIdent<t>                (. IF NOT SymTab.SetProcRes(t) THEN
 1213                                               SemError(235) END;
 1214                                             Lower.SetProcRes(t);
 1215                                             QbeGen.SetFuncRes(t);
 1216                                             IF (t #
 1217                                                SymTab.InvalidType)
 1218   AND ((SymTab.ClassOf(t)
 1219                                                   = SymTab.ClArray)
 1220                                                OR (SymTab.ClassOf(t)
 1221                                                   = SymTab.ClRecord)
 1222                                                OR (SymTab.ClassOf(t)
 1223                                                   = SymTab.ClSet)
 1224                                                OR (SymTab.ClassOf(t)
 1225                                                   = SymTab.ClClass)) THEN
 1226                                               SemError(230) END; .) ] .
 1227    FormalParams
 1228      = "(" [ ParamSection { ";" ParamSection } ] ")" .
 1229    ParamSection                          (. VAR t: SymTab.TypeIndex;
 1230                                               nm: SymTab.Name;
 1231                                               i: CARDINAL;
 1232                                               isV: BOOLEAN; .)
 1233      =                                   (. isV := FALSE; .)
 1234        [ "VAR"                           (. isV := TRUE; .) ]
 1235        ParIdents<isV> ":" Type<t, TRUE>  (. i := 0;
 1236                                             WHILE i < SymTab.PendCount() DO
 1237                                               SymTab.PendName(i, nm);
 1238                                               Lower.NoteParam(nm, t, isV);
 1239                                               Lower.NoteVar(nm, SymTab.KindParam, t);
 1240                                               (* value open arrays are
 1241                                                  passed as descriptor
 1242                                                  addresses (no copy):
 1243                                                  same representation as
 1244                                                  VAR formals *)
 1245                                               IF NOT QbeGen.FuncParam(nm,
 1246                                                    isV
 1247                                                    OR SymTab.IsOpenArray(t),
 1248                                                    t) THEN
 1249                                                 SemError(233) END;
 1250                                               INC(i)
 1251                                             END;
 1252                                             IF NOT SymTab.FixPending(t) THEN
 1253                                               SemError(235) END; .) .
 1254    (* Nested procedures lower like top-level ones (4.2): the
 1255       static link gives them their parent's frame. Methods keep
 1256       parse-now/230-later. *)
 1257    ProcDecl                              (. VAR pn: SymTab.Name;
 1258                                               astNode: AST.Node; .)
 1259      = ProcHeading<pn, SymTab.InvalidType> ";"
 1260                                          (. astNode := AST.MakeNode(AST.NkProcDecl);
 1261                                             AST.SetOp(astNode, 0);
 1262                                             AST.SetChild(astNode, 0,
 1263                                               AST.MakeLeaf(AST.NkIdent, pn));
 1264                                             Lower.NoteProcNode(astNode); .)
 1265        ( "FORWARD"                       (. AST.SetOp(astNode, 1);
 1266                                             astDecl := astNode;
 1267                                             Lower.ScopeLeave;
 1268                                             SymTab.MarkFwd;
 1269                                             SymTab.CloseProc;
 1270                                             QbeGen.AbortFunc; .)
 1271        | "EXTERNAL"                      (. AST.SetOp(astNode, 2);
 1272                                             astDecl := astNode;
 1273                                             Lower.MarkProcExternal;
 1274                                             Lower.ScopeLeave;
 1275                                             SymTab.MarkExternal("");
 1276                                             SymTab.CloseProc;
 1277                                             QbeGen.AbortFunc; .)
 1278        |                                 (. QbeGen.EndFuncHeader; .)
 1279          Block<pn>                       (. AST.SetChild(astNode, 1, astStmt);
 1280                                             AST.SetChild(astNode, 2, astBlkDecls);
 1281                                             astDecl := astNode;
 1282                                             Lower.ScopeLeave;
 1283                                             SymTab.CloseProc;
 1284                                             QbeGen.EndFunc(
 1285                                               SymTab.ProcRes(pn)); .) ) .
 1286    Block<pn: SymTab.Name>                (. VAR m2: SymTab.Name; .)
 1287      = DeclSeq                           (. astBlkDecls := astDecl;
 1288                                             astStmt := AST.NoNode; .)
 1289        [ "BEGIN"
 1290          [ StatSeq ] ]
 1291        "END"
 1292        GetIdent<m2>                      (. IF NOT SymTab.Equal(pn, m2) THEN
 1293                                               SemError(202) END; .) .
 1294    StatSeq                               (. VAR astSeq, astTail: AST.Node; .)
 1295      =                                   (. astSeq := AST.NoNode;
 1296                                             astTail := AST.NoNode; .)
 1297        Statement                         (. AstAppend(AST.NkBlock,
 1298                                               astSeq, astTail, astStmt); .)
 1299        { ";" [ Statement                 (. AstAppend(AST.NkBlock,
 1300                                               astSeq, astTail, astStmt); .) ] }
 1301                                          (. astStmt := astSeq; .) .
 1302    (* Trailing/empty statements (`a; ; b`, Coco/R's generated `;;`)
 1303       are accepted: the statement after ';' is optional. *)
 1304    Statement                             (. VAR lx: QbeGen.QVal; .)
 1305      = (. astStmt := AST.NoNode; .)
 1306        ( AssOrCall
 1307      | IfStat
 1308      | WhileStat
 1309      | RepeatStat
 1310      | LoopStat
 1311      | ForStat
 1312      | CaseStat
 1313      | WithStat
 1314      | ReturnStat
 1315      | HaltStat
 1316      | NewStat
 1317      | DisposeStat
 1318      | IncDecStat
 1319      | InclExclStat
 1320      | "EXIT"                            (. IF QbeGen.TopLoop(lx) THEN
 1321                                               QbeGen.Jmp(lx)
 1322                                             ELSE SemError(230) END;
 1323                                             astStmt := AST.MakeNode(AST.NkExit); .) ) .
 1324    (* INCL(set, elem) / EXCL(set, elem): PIM set-element builtins. *)
 1325    InclExclStat                          (. VAR at, et2: SymTab.TypeIndex;
 1326                                               dk: INTEGER;
 1327                                               qd, qe: QbeGen.QVal;
 1328                                               qn: SymTab.Name;
 1329                                               sfx, isInc: BOOLEAN;
 1330                                               astNode, astD: AST.Node; .)
 1331      = ( "INCL"                          (. isInc := TRUE; .)
 1332        | "EXCL"                          (. isInc := FALSE; .) )
 1333        "(" Design<at, dk, qd, qn, sfx> (. astD := astCur; .) ","
 1334        Expr<et2, qe> ")"
 1335                                          (. astNode := AST.MakeNode(AST.NkCall);
 1336                                             IF isInc THEN
 1337                                               AST.SetChild(astNode, 0,
 1338                                                 AST.MakeLeaf(AST.NkIdent, "INCL"))
 1339                                             ELSE AST.SetChild(astNode, 0,
 1340                                                 AST.MakeLeaf(AST.NkIdent, "EXCL"))
 1341                                             END;
 1342                                             IF astD # AST.NoNode THEN
 1343                                               AST.SetChild(astNode, 1, astD) END;
 1344                                             IF astCur # AST.NoNode THEN
 1345                                               AST.SetChild(astNode, 2, astCur) END;
 1346                                             astStmt := astNode; .)
 1347                                          (. IF at = SymTab.InvalidType THEN
 1348                                             ELSIF SymTab.ClassOf(at) #
 1349                                                   SymTab.ClSet THEN
 1350                                               SemError(222)
 1351                                             ELSE
 1352                                               IF isInc THEN
 1353                                                 QbeGen.SetBit(qd, qe,
 1354                                                   SymTab.SetBaseLo(at),
 1355                                                   SymTab.SetCount(at))
 1356                                               ELSE
 1357                                                 QbeGen.SetClearBit(qd, qe,
 1358                                                   SymTab.SetBaseLo(at),
 1359                                                   SymTab.SetCount(at))
 1360                                               END
 1361                                             END; .) .
 1362    (* INC(v [,step]) / DEC(v [,step]) as builtin statements over an
 1363       integer designator. *)
 1364    IncDecStat                            (. VAR dt, et2: SymTab.TypeIndex;
 1365                                               dk: INTEGER;
 1366                                               qd, qv, qn2, qstep:
 1367                                                 QbeGen.QVal;
 1368                                               qn: SymTab.Name;
 1369                                               sfx, isInc: BOOLEAN;
 1370                                               astNode, astD, astStep:
 1371                                                 AST.Node; .)
 1372      =                                   (. isInc := TRUE; .)
 1373        ( "INC"                           (. isInc := TRUE; .)
 1374        | "DEC"                           (. isInc := FALSE; .) )
 1375        "("                               (. QbeGen.CopyOp("1", qstep); astStep := AST.NoNode; .)
 1376        Design<dt, dk, qd, qn, sfx> (. astD := astCur; .)
 1377        [ "," Expr<et2, qstep> (. astStep := astCur; .) ]
 1378        ")"                               (. astNode := AST.MakeNode(AST.NkCall);
 1379                                             IF isInc THEN
 1380                                               AST.SetChild(astNode, 0,
 1381                                                 AST.MakeLeaf(AST.NkIdent, "INC"))
 1382                                             ELSE AST.SetChild(astNode, 0,
 1383                                                 AST.MakeLeaf(AST.NkIdent, "DEC"))
 1384                                             END;
 1385                                             IF astD # AST.NoNode THEN
 1386                                               AST.SetChild(astNode, 1, astD) END;
 1387                                             IF astStep # AST.NoNode THEN
 1388                                               AST.SetChild(astNode, 2, astStep) END;
 1389                                             astStmt := astNode; .)                               (. IF dt = SymTab.InvalidType THEN
 1390                                             ELSIF (dk # SymTab.KindVar)
 1391   AND (dk # SymTab.KindParam)
 1392   AND (dk # SymTab.KindField) THEN
 1393                                               SemError(210)
 1394                                             ELSIF NOT SymTab.IsIntFamily(dt) THEN
 1395                                               SemError(211)
 1396                                             ELSE
 1397                                               IF sfx
 1398                                                  OR (dk = SymTab.KindField) THEN
 1399                                                 QbeGen.ElemLoad(qd, dt, qv)
 1400                                               ELSE QbeGen.LoadVar(qn,
 1401                                                 FALSE, qv)
 1402                                               END;
 1403                                               QbeGen.NewTemp(qn2);
 1404                                               IF isInc THEN
 1405                                                 QbeGen.Op3("add", qn2, qv,
 1406                                                   qstep, FALSE)
 1407                                               ELSE QbeGen.Op3("sub", qn2, qv,
 1408                                                   qstep, FALSE)
 1409                                               END;
 1410                                               IF sfx
 1411                                                  OR (dk = SymTab.KindField) THEN
 1412                                                 QbeGen.ElemStore(qd, qn2,
 1413                                                   dt)
 1414                                               ELSE QbeGen.StoreVar(qn,
 1415                                                 qn2, FALSE)
 1416                                               END
 1417                                             END; .) .
 1418    (* NEW/DISPOSE as builtin statements (no call syntax until step 4).
 1419       Targets are pointer designators; DISPOSE nils afterwards (safer
 1420       than Wirth-undefined; documented). DISPOSE is shallow. *)
 1421    NewStat                               (. VAR dt: SymTab.TypeIndex;
 1422                                               dk: INTEGER;
 1423                                               qd, qm: QbeGen.QVal;
 1424                                               qn: SymTab.Name;
 1425                                               sfx: BOOLEAN;
 1426                                               bt: SymTab.TypeIndex;
 1427                                               astNode, astD: AST.Node; .)
 1428      = "NEW" "(" Design<dt, dk, qd, qn, sfx> (. astD := astCur; .) ")"
 1429                                          (. astNode := AST.MakeNode(AST.NkCall);
 1430                                             AST.SetChild(astNode, 0,
 1431                                               AST.MakeLeaf(AST.NkIdent, "NEW"));
 1432                                             IF astD # AST.NoNode THEN
 1433                                               AST.SetChild(astNode, 1, astD) END;
 1434                                             astStmt := astNode; .)
 1435                                          (. IF dt = SymTab.InvalidType THEN
 1436                                             ELSIF (dk # SymTab.KindVar)
 1437   AND (dk # SymTab.KindParam)
 1438   AND (dk # SymTab.KindField) THEN
 1439                                               SemError(210)
 1440                                             ELSIF SymTab.ClassOf(dt) #
 1441                                                   SymTab.ClPtr THEN
 1442                                               SemError(219)
 1443                                             ELSE bt := SymTab.PtrBase(dt);
 1444                                               IF bt #
 1445                                                  SymTab.InvalidType THEN
 1446                                                 QbeGen.NewHeap(bt, qm);
 1447                                                 QbeGen.InitHeap(qm, bt);
 1448                                                 IF sfx
 1449                                                    OR (dk =
 1450                                                       SymTab.KindField) THEN
 1451                                                   QbeGen.ElemStore(qd, qm,
 1452                                                     dt)
 1453                                                 ELSE QbeGen.StorePtr(qn,
 1454                                                   qm)
 1455                                                 END
 1456                                               END
 1457                                             END; .) .
 1458    DisposeStat                           (. VAR dt: SymTab.TypeIndex;
 1459                                               dk: INTEGER;
 1460                                               qd, qv: QbeGen.QVal;
 1461                                               qn: SymTab.Name;
 1462                                               sfx: BOOLEAN;
 1463                                               astNode, astD: AST.Node; .)
 1464      = "DISPOSE" "(" Design<dt, dk, qd, qn, sfx> (. astD := astCur; .) ")"
 1465                                          (. astNode := AST.MakeNode(AST.NkCall);
 1466                                             AST.SetChild(astNode, 0,
 1467                                               AST.MakeLeaf(AST.NkIdent, "DISPOSE"));
 1468                                             IF astD # AST.NoNode THEN
 1469                                               AST.SetChild(astNode, 1, astD) END;
 1470                                             astStmt := astNode; .)
 1471                                          (. IF dt = SymTab.InvalidType THEN
 1472                                             ELSIF (dk # SymTab.KindVar)
 1473   AND (dk # SymTab.KindParam)
 1474   AND (dk # SymTab.KindField) THEN
 1475                                               SemError(210)
 1476                                             ELSIF SymTab.ClassOf(dt) #
 1477                                                   SymTab.ClPtr THEN
 1478                                               SemError(219)
 1479                                             ELSE
 1480                                               IF sfx
 1481                                                  OR (dk =
 1482                                                     SymTab.KindField) THEN
 1483                                                 QbeGen.ElemLoad(qd, dt,
 1484                                                   qv)
 1485                                               ELSE QbeGen.LoadPtr(qn, qv)
 1486                                               END;
 1487                                               QbeGen.FreeHeap(qv);
 1488                                               IF sfx
 1489                                                  OR (dk =
 1490                                                     SymTab.KindField) THEN
 1491                                                 QbeGen.ElemStore(qd, "0",
 1492                                                   dt)
 1493                                               ELSE QbeGen.StorePtr(qn,
 1494                                                 "0")
 1495                                               END
 1496                                             END; .) .
 1497    (* WITH pushes each record's fields (inner wins) plus its base
 1498       address; field designators resolve through both stacks. *)
 1499    WithStat                              (. VAR nW: CARDINAL;
 1500                                               astNode: AST.Node; .)
 1501      = "WITH"                            (. nW := 0;
 1502                                             astNode := AST.MakeNode(AST.NkWith); .)
 1503        WithItem<nW, astNode> { "," WithItem<nW, astNode> }
 1504        "DO"                              (. astStmt := AST.NoNode; .)
 1505        [ StatSeq ] "END"                 (. AST.SetChild(astNode,
 1506                                             AST.NChild(astNode), astStmt);
 1507                                             astStmt := astNode;
 1508                                             WHILE nW > 0 DO
 1509                                               SymTab.PopScope;
 1510                                               QbeGen.PopWith;
 1511                                               DEC(nW)
 1512                                             END; .) .
 1513    WithItem<VAR nW: CARDINAL; wnode: AST.Node>
 1514                                          (. VAR dt: SymTab.TypeIndex;
 1515                                               dk: INTEGER;
 1516                                               qd, qe: QbeGen.QVal;
 1517                                               qn: SymTab.Name;
 1518                                               sfx: BOOLEAN; .)
 1519      = Design<dt, dk, qd, qn, sfx>
 1520                                          (. IF astCur # AST.NoNode THEN
 1521                                               AST.SetChild(wnode,
 1522                                                 AST.NChild(wnode), astCur) END;
 1523                                             IF dt = SymTab.InvalidType THEN
 1524                                             ELSIF (SymTab.ClassOf(dt) #
 1525                                                    SymTab.ClRecord)
 1526   AND (SymTab.ClassOf(dt) #
 1527                                                   SymTab.ClClass) THEN
 1528                                               SemError(215)
 1529                                             ELSIF SymTab.PushRecord(dt) THEN
 1530                                               QbeGen.PushWith(qd);
 1531                                               INC(nW)
 1532                                             END; .) .
 1533    (* Assignment or procedure-statement call (4.1, module level).
 1534       Bare `P;` is a syntax error; function-as-statement is 233. *)
 1535    AssOrCall                             (. VAR dt, et: SymTab.TypeIndex;
 1536                                               dk: INTEGER;
 1537                                               qd, qe, qt, ql: QbeGen.QVal;
 1538                                               qn: SymTab.Name;
 1539                                               ct2, res0: SymTab.TypeIndex;
 1540                                               q2, mg0: QbeGen.QVal;
 1541                                               isR, conv, wconv: BOOLEAN;
 1542                                               called, sfx: BOOLEAN;
 1543                                               astLhs: AST.Node; .)
 1544      = Design<dt, dk, qd, qn, sfx>
 1545        (. astLhs := astCur; astNArgs := 0; .)
 1546        ( ":="
 1547          Expr<et, qe>                    (. astStmt := AST.MakeBin(
 1548                                               AST.NkAssign, 0, astLhs, astCur);
 1549                                             IF (dt # SymTab.InvalidType)
 1550   AND (dk # SymTab.KindVar)
 1551   AND (dk # SymTab.KindParam)
 1552   AND (dk # SymTab.KindField) THEN
 1553                                             SemError(210)
 1554                                           ELSIF NOT SymTab.Assignable(et,
 1555                                                    dt) THEN
 1556                                             SemError(210)
 1557                                           ELSIF (dt # SymTab.InvalidType)
 1558   AND (SymTab.ClassOf(dt) =
 1559                                                 SymTab.ClClass) THEN
 1560                                             SemError(230) END;
 1561                                           isR := (dt #
 1562                                                   SymTab.InvalidType)
 1563   AND (SymTab.ClassOf(dt)
 1564                                                     = SymTab.ClReal);
 1565                                           conv := isR
 1566   AND SymTab.IsIntFamily(et);
 1567                                           wconv := (dt #
 1568                                                     SymTab.InvalidType)
 1569   AND SymTab.IsLongFamily(dt)
 1570   AND SymTab.IsIntFamily(et);
 1571                                           IF ((dk = SymTab.KindVar)
 1572                                               OR (dk = SymTab.KindParam)
 1573                                               OR (dk = SymTab.KindField))
 1574   AND (dt # SymTab.InvalidType)
 1575   AND (et # SymTab.InvalidType)
 1576   AND (SymTab.ClassOf(dt) #
 1577                                                 SymTab.ClClass) THEN
 1578                                             IF sfx
 1579                                                OR (dk = SymTab.KindField) THEN
 1580                                               IF SymTab.ClassOf(dt) =
 1581                                                  SymTab.ClArray THEN
 1582                                                 IF (et # SymTab.InvalidType)
 1583    AND (SymTab.ClassOf(et) = SymTab.ClUStr)
 1584    AND SymTab.IsUCharArray(dt) THEN
 1585                                                   QbeGen.UAssign(qd, qe)
 1586                                                 ELSIF SymTab.StrCompat(dt,
 1587                                                      et) THEN
 1588                                                   QbeGen.StrAssign(qd,
 1589                                                     qe)
 1590                                                 ELSE
 1591                                                   QbeGen.CopyArray(qd,
 1592                                                     qe, dt)
 1593                                                 END
 1594                                               ELSIF SymTab.ClassOf(dt) =
 1595                                                   SymTab.ClSet THEN
 1596                                                 QbeGen.CopySet(qd, qe,
 1597                                                   SymTab.SetWords(dt),
 1598                                                   SymTab.SetWords(et))
 1599                                               ELSIF SymTab.ClassOf(dt) =
 1600                                                   SymTab.ClRecord THEN
 1601                                                 QbeGen.CopyRecord(qd, qe,
 1602                                                   dt)
 1603                                               ELSIF SymTab.IsLongFamily(dt) THEN
 1604                                                 IF wconv THEN
 1605                                                   QbeGen.WidenLong(qe, ql);
 1606                                                   QbeGen.ElemStore(qd, ql,
 1607                                                     dt)
 1608                                                 ELSE QbeGen.ElemStore(qd, qe,
 1609                                                   dt)
 1610                                                 END
 1611                                               ELSIF conv THEN
 1612                                                 QbeGen.ConvIR(qe, qt);
 1613                                                 QbeGen.ElemStore(qd, qt,
 1614                                                   dt)
 1615                                               ELSE QbeGen.ElemStore(qd, qe,
 1616                                                 dt)
 1617                                               END
 1618                                             ELSIF SymTab.ClassOf(dt) =
 1619                                                   SymTab.ClArray THEN
 1620                                               IF (et # SymTab.InvalidType)
 1621    AND (SymTab.ClassOf(et) = SymTab.ClUStr)
 1622    AND SymTab.IsUCharArray(dt) THEN
 1623                                                 QbeGen.UAssign(qd, qe)
 1624                                               ELSIF SymTab.StrCompat(dt,
 1625                                                    et) THEN
 1626                                                 QbeGen.StrAssign(qd, qe)
 1627                                               ELSE
 1628                                                 QbeGen.CopyArray(qd, qe,
 1629                                                   dt)
 1630                                               END
 1631                                             ELSIF SymTab.ClassOf(dt) =
 1632                                                   SymTab.ClSet THEN
 1633                                               QbeGen.CopySet(qd, qe,
 1634                                                 SymTab.SetWords(dt),
 1635                                                 SymTab.SetWords(et))
 1636                                             ELSIF SymTab.ClassOf(dt) =
 1637                                                   SymTab.ClRecord THEN
 1638                                               QbeGen.CopyRecord(qd, qe, dt)
 1639                                             ELSIF (SymTab.ClassOf(dt) =
 1640                                                   SymTab.ClPtr)
 1641                                                OR (SymTab.ClassOf(dt) =
 1642                                                   SymTab.ClProc) THEN
 1643                                               QbeGen.StorePtr(qn, qe)
 1644                                             ELSIF SymTab.IsLongFamily(dt) THEN
 1645                                               IF wconv THEN
 1646                                                 QbeGen.WidenLong(qe, ql);
 1647                                                 QbeGen.StoreLong(qn, ql)
 1648                                               ELSE QbeGen.StoreLong(qn, qe)
 1649                                               END
 1650                                             ELSIF conv THEN
 1651                                               QbeGen.ConvIR(qe, qt);
 1652                                               QbeGen.StoreVar(qn, qt, TRUE)
 1653                                             ELSE
 1654                                               QbeGen.StoreVar(qn, qe, isR)
 1655                                             END
 1656                                           END; .)
 1657        | ArgList<qn, dt, qd, FALSE, FALSE, methCls, ct2, q2, called>
 1658                                          (. astStmt := AstCallNode(astLhs); .)
 1659        |                                 (* bare `P;`: proper parameterless
 1660                                              procedure call; anything else
 1661                                              here is 233 (was a bare syntax
 1662                                              error before 4.2) *)
 1663                                          (. astStmt := AstCallNode(astLhs);
 1664                                              IF (dk = SymTab.KindProc)
 1665   AND NOT sfx THEN
 1666                                               res0 := SymTab.ProcRes(qn);
 1667                                               IF res0 #
 1668                                                  SymTab.InvalidType THEN
 1669                                                 SemError(233)
 1670                                               ELSIF SymTab.ProcNPar(qn) #
 1671                                                       0 THEN
 1672                                                 SemError(233)
 1673                                               ELSE QbeGen.Mangled(qn,
 1674                                                 SymTab.ProcUid(qn), mg0);
 1675                                                 QbeGen.CallBegin(mg0,
 1676                                                   res0,
 1677                                                   SymTab.ProcDepthOf(qn),
 1678                                                   SymTab.IsExternal(qn));
 1679                                                 QbeGen.CallEnd(FALSE, q2)
 1680                                               END
 1681                                             ELSE SemError(233)
 1682                                             END; .) ) .
 1683    (* Actual-parameter list shared by statement and expression calls.
 1684       want selects CallEnd's result handling; t/q carry the call
 1685       value (statement calls discard). Arity/type failures are 233;
 1686       evaluation code still emits so the .ssa stays assembleable. *)
 1687    ArgList<pn: SymTab.Name; pt: SymTab.TypeIndex; callee: QbeGen.QVal;
 1688            want: BOOLEAN; soft: BOOLEAN; methCls: SymTab.TypeIndex;
 1689            VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal;
 1690            VAR called: BOOLEAN>          (. VAR i, np: CARDINAL;
 1691                                               vs: INTEGER;
 1692                                               res: SymTab.TypeIndex;
 1693                                               mg: QbeGen.QVal;
 1694                                               ok, ind, isMeth, va: BOOLEAN; .)
 1695      = "("                               (. called := TRUE;
 1696                                             ok := TRUE;
 1697                                             ind := FALSE;
 1698                                             isMeth := methCls #
 1699                                               SymTab.InvalidType;
 1700                                             IF isMeth THEN
 1701                                               (* class method: the
 1702                                                  receiver is armed.
 1703                                                  Virtual -> dispatch
 1704                                                  through the vtable;
 1705                                                  otherwise a static
 1706                                                  call. *)
 1707                                               res := SymTab.ClassMethodRes(
 1708                                                 methCls, pn);
 1709                                               vs := SymTab.VirtSlot(
 1710                                                 methCls, pn);
 1711                                               IF vs >= 0 THEN
 1712                                                 QbeGen.VirtCallBegin(
 1713                                                   callee, vs, res)
 1714                                               ELSE
 1715                                                 QbeGen.Mangled(pn,
 1716                                                   SymTab.ClassMethodUid(
 1717                                                   methCls, pn), mg);
 1718                                                 QbeGen.CallBegin(mg, res, 0,
 1719                                                   FALSE)
 1720                                               END
 1721                                             ELSIF SymTab.SymKind(pn) =
 1722                                                SymTab.KindProc THEN
 1723                                               res := SymTab.ProcRes(pn);
 1724                                               QbeGen.Mangled(pn,
 1725                                                 SymTab.ProcUid(pn), mg);
 1726                                               QbeGen.CallBegin(mg, res,
 1727                                                 SymTab.ProcDepthOf(pn),
 1728                                                 SymTab.IsExternal(pn))
 1729                                             ELSIF (pt # SymTab.InvalidType)
 1730    AND (SymTab.ClassOf(pt) = SymTab.ClProc) THEN
 1731                                               ind := TRUE;
 1732                                               res :=
 1733                                                 SymTab.ProcTypeRes(pt);
 1734                                               QbeGen.CallBeginInd(callee,
 1735                                                 res, FALSE)
 1736                                             ELSE SemError(233);
 1737                                               ok := FALSE;
 1738                                               res := SymTab.InvalidType
 1739                                             END;
 1740                                             i := 0; .)
 1741        [ ActParam<pn, pt, ind, methCls, i>        (. INC(i); .)
 1742          { "," ActParam<pn, pt, ind, methCls, i>  (. INC(i); .) } ]
 1743        ")"                               (. IF ok THEN
 1744                                               IF isMeth THEN
 1745                                                 np := SymTab.ClassMethodNPar(
 1746                                                   methCls, pn)
 1747                                               ELSIF ind THEN
 1748                                                 np := SymTab.ProcTypeNPar(pt)
 1749                                               ELSE np := SymTab.ProcNPar(pn)
 1750                                               END;
 1751                                               va := (NOT isMeth) AND (NOT ind)
 1752                                                 AND (SymTab.SymKind(pn) =
 1753                                                      SymTab.KindProc)
 1754                                                 AND SymTab.Varargs(pn);
 1755                                               IF (i # np) AND NOT va THEN
 1756                                                 SemError(233); ok := FALSE
 1757                                               END
 1758                                             END;
 1759                                             IF NOT ok THEN
 1760                                               t := SymTab.InvalidType;
 1761                                               QbeGen.CopyOp("0", q)
 1762                                             ELSIF want THEN
 1763                                               IF res =
 1764                                                  SymTab.InvalidType THEN
 1765                                                 SemError(233);
 1766                                                 t := SymTab.InvalidType;
 1767                                                 QbeGen.CopyOp("0", q)
 1768                                               ELSE t := res;
 1769                                                 QbeGen.CallEnd(TRUE, q)
 1770                                               END
 1771                                             ELSE
 1772                                               IF res #
 1773                                                  SymTab.InvalidType THEN
 1774                                                 SemError(233)
 1775                                               END;
 1776                                               t := SymTab.InvalidType;
 1777                                               QbeGen.CopyOp("0", q);
 1778                                               QbeGen.CallEnd(FALSE, q)
 1779                                             END; .) .
 1780    (* One actual: VAR formals take recorded designator addresses
 1781       (233 otherwise); value formals take converted expressions. *)
 1782    ActParam<pn: SymTab.Name; pt: SymTab.TypeIndex; ind: BOOLEAN;
 1783             methCls: SymTab.TypeIndex; i: CARDINAL>
 1784                                          (. VAR at, ft: SymTab.TypeIndex;
 1785                                               qe, qa, qt: QbeGen.QVal;
 1786                                               isV, conv, va: BOOLEAN;
 1787                                               cl: CHAR;
 1788                                               savedN, aj: CARDINAL;
 1789                                               savedArgs: ARRAY [0 .. 31]
 1790                                                 OF AST.Node; .)
 1791      =                                   (. (* Parsing the actual can clobber
 1792                                               the enclosing call's argument
 1793                                               list (Factor resets astNArgs),
 1794                                               so save/restore it. *)
 1795                                             savedN := astNArgs; aj := 0;
 1796                                             WHILE aj <= HIGH(astArgs) DO
 1797                                               savedArgs[aj] := astArgs[aj];
 1798                                               INC(aj)
 1799                                             END; .)
 1800        Expr<at, qe>                      (. astNArgs := savedN; aj := 0;
 1801                                             WHILE aj <= HIGH(astArgs) DO
 1802                                               astArgs[aj] := savedArgs[aj];
 1803                                               INC(aj)
 1804                                             END;
 1805                                             IF astNArgs <= HIGH(astArgs) THEN
 1806                                               astArgs[astNArgs] := astCur;
 1807                                               INC(astNArgs)
 1808                                             END;
 1809                                             va := (NOT ind)
 1810                                               AND (methCls =
 1811                                                  SymTab.InvalidType)
 1812                                               AND (SymTab.SymKind(pn) =
 1813                                                  SymTab.KindProc)
 1814                                               AND SymTab.Varargs(pn);
 1815                                             IF ind THEN
 1816                                               ft :=
 1817                                                 SymTab.ProcTypeParamType(pt,
 1818                                                   i);
 1819                                               isV :=
 1820                                                 SymTab.ProcTypeParamIsVar(pt,
 1821                                                   i)
 1822                                             ELSIF methCls #
 1823                                                SymTab.InvalidType THEN
 1824                                               ft :=
 1825                                                 SymTab.ClassMethodParamType(
 1826                                                 methCls, pn, i);
 1827                                               isV :=
 1828                                                 SymTab.ClassMethodParamIsVar(
 1829                                                 methCls, pn, i)
 1830                                             ELSE
 1831                                               ft := SymTab.ParamType(pn, i);
 1832                                               isV := SymTab.ParamIsVar(pn, i)
 1833                                             END;
 1834                                             IF (at = SymTab.InvalidType) THEN
 1835                                             ELSIF ft = SymTab.InvalidType THEN
 1836                                               IF va THEN
 1837                                                 QbeGen.CArgAdd(qe, at, qa, cl)
 1838                                               END
 1839                                             ELSIF isV THEN
 1840                                               IF (SymTab.ClassOf(at)
 1841                                                  = SymTab.ClChar)
 1842    AND (SymTab.ClassOf(ft) = SymTab.ClArray)
 1843    AND (SymTab.ClassOf(SymTab.ArrayElem(ft))
 1844         = SymTab.ClChar)
 1845    AND QbeGen.IsImm(qe) THEN
 1846                                                 (* 1-char string
 1847                                                    literal passed to
 1848                                                    a VAR ARRAY OF CHAR *)
 1849                                                 QbeGen.DeclCharStr(qe,
 1850                                                      qa);
 1851                                                 IF NOT QbeGen.CallArg(qa,
 1852                                                    "l") THEN
 1853                                                   SemError(233)
 1854                                                 END
 1855                                               ELSIF NOT QbeGen.AddrOfVal(qe,
 1856                                                    qa) THEN
 1857                                                 SemError(233)
 1858                                               ELSIF NOT SymTab.VarParamOk(at,
 1859                                                        ft) THEN
 1860                                                 SemError(233)
 1861                                               ELSIF NOT QbeGen.CallArg(qa,
 1862                                                        "l") THEN
 1863                                                 SemError(233)
 1864                                               END
 1865                                             ELSE
 1866                                               IF (SymTab.ClassOf(at)
 1867                                                  = SymTab.ClChar)
 1868    AND (SymTab.ClassOf(ft) = SymTab.ClArray)
 1869    AND (SymTab.ClassOf(SymTab.ArrayElem(ft))
 1870         = SymTab.ClChar)
 1871    AND QbeGen.IsImm(qe) THEN
 1872                                                 (* 1-char string
 1873                                                    literal passed to
 1874                                                    ARRAY OF CHAR *)
 1875                                                 QbeGen.DeclCharStr(qe,
 1876                                                      qa);
 1877                                                 IF NOT QbeGen.CallArg(qa,
 1878                                                    "l") THEN
 1879                                                   SemError(233)
 1880                                                 END
 1881                                               ELSIF NOT SymTab.Assignable(at,
 1882                                                    ft) THEN
 1883                                                 SemError(233)
 1884                                               ELSE
 1885                                                 conv := (SymTab.ClassOf(
 1886                                                   ft) = SymTab.ClReal)
 1887   AND SymTab.IsIntFamily(at);
 1888                                                 IF conv THEN
 1889                                                   QbeGen.ConvIR(qe, qt);
 1890                                                   IF NOT QbeGen.CallArg(qt,
 1891                                                      "d") THEN
 1892                                                     SemError(233)
 1893                                                   END
 1894                                                 ELSIF NOT QbeGen.CallArg(qe,
 1895                                                   QbeGen.ArgClass(ft)) THEN
 1896                                                   SemError(233)
 1897                                                 END
 1898                                               END
 1899                                             END; .) .
 1900    IfStat                                (. VAR t: SymTab.TypeIndex;
 1901                                               q, lThen, lElse, lEnd:
 1902                                                 QbeGen.QVal;
 1903                                               hasElse: BOOLEAN;
 1904                                               astCond, astIf, astLast,
 1905                                               astNode: AST.Node; .)
 1906      = "IF" (. hasElse := FALSE; .)
 1907        Expr<t, q> (. astCond := astCur; astStmt := AST.NoNode;
 1908                                             IF NOT SymTab.BoolCheck(t) THEN
 1909                                               SemError(214) END;
 1910                                             QbeGen.NewLabel(lThen);
 1911                                             QbeGen.NewLabel(lElse);
 1912                                             QbeGen.NewLabel(lEnd);
 1913                                             QbeGen.Jnz(q, lThen, lElse);
 1914                                             QbeGen.EmitLabel(lThen); .)
 1915        "THEN" [ StatSeq ]                (. astNode := AST.MakeNode(AST.NkIf);
 1916                                             AST.SetChild(astNode, 0, astCond);
 1917                                             AST.SetChild(astNode, 1, astStmt);
 1918                                             astIf := astNode;
 1919                                             astLast := astNode;
 1920                                             QbeGen.Jmp(lEnd); .)
 1921        { "ELSIF"                         (. QbeGen.EmitLabel(lElse);
 1922                                             QbeGen.NewLabel(lElse); .)
 1923          Expr<t, q> (. astCond := astCur; astStmt := AST.NoNode;
 1924                                             IF NOT SymTab.BoolCheck(t) THEN
 1925                                               SemError(214) END;
 1926                                             QbeGen.NewLabel(lThen);
 1927                                             QbeGen.Jnz(q, lThen, lElse);
 1928                                             QbeGen.EmitLabel(lThen); .)
 1929          "THEN" [ StatSeq ]              (. astNode := AST.MakeNode(AST.NkIf);
 1930                                             AST.SetChild(astNode, 0, astCond);
 1931                                             AST.SetChild(astNode, 1, astStmt);
 1932                                             AST.SetChild(astLast, 2, astNode);
 1933                                             astLast := astNode;
 1934                                             QbeGen.Jmp(lEnd); .) }
 1935        [ "ELSE"                          (. QbeGen.EmitLabel(lElse);
 1936                                             hasElse := TRUE;
 1937                                             astStmt := AST.NoNode; .)
 1938          [ StatSeq ] (. AST.SetChild(astLast, 2, astStmt); .) ]
 1939        "END" (. astStmt := astIf;
 1940                                             IF hasElse THEN
 1941                                               QbeGen.EmitLabel(lEnd)
 1942                                             ELSE QbeGen.EmitLabel(lElse);
 1943                                               QbeGen.EmitLabel(lEnd)
 1944                                             END; .) .
 1945    WhileStat                             (. VAR t: SymTab.TypeIndex;
 1946                                               q, lTop, lBody, lEnd:
 1947                                                 QbeGen.QVal;
 1948                                               astCond, astNode: AST.Node; .)
 1949      = "WHILE" (. astStmt := AST.NoNode;
 1950                                             QbeGen.NewLabel(lTop);
 1951                                             QbeGen.NewLabel(lBody);
 1952                                             QbeGen.NewLabel(lEnd);
 1953                                             QbeGen.EmitLabel(lTop); .)
 1954        Expr<t, q> (. astCond := astCur;
 1955                                             IF NOT SymTab.BoolCheck(t) THEN
 1956                                               SemError(214) END;
 1957                                             QbeGen.Jnz(q, lBody, lEnd);
 1958                                             QbeGen.EmitLabel(lBody); .)
 1959        "DO" [ StatSeq ]                      (. astNode := AST.MakeNode(AST.NkWhile);
 1960                                             AST.SetChild(astNode, 0, astCond);
 1961                                             AST.SetChild(astNode, 1, astStmt);
 1962                                             astStmt := astNode;
 1963                                             QbeGen.Jmp(lTop); .)
 1964        "END"                             (. QbeGen.EmitLabel(lEnd); .) .
 1965    RepeatStat                            (. VAR t: SymTab.TypeIndex;
 1966                                               q, lTop, lEnd: QbeGen.QVal;
 1967                                               astCond, astBody, astNode:
 1968                                                 AST.Node; .)
 1969      = "REPEAT" (. astStmt := AST.NoNode;
 1970                                             QbeGen.NewLabel(lTop);
 1971                                             QbeGen.NewLabel(lEnd);
 1972                                             QbeGen.EmitLabel(lTop); .)
 1973        [ StatSeq ] (. astBody := astStmt; .)
 1974        "UNTIL" Expr<t, q> (. astCond := astCur;
 1975                                             astNode := AST.MakeNode(AST.NkRepeat);
 1976                                             AST.SetChild(astNode, 0, astBody);
 1977                                             AST.SetChild(astNode, 1, astCond);
 1978                                             astStmt := astNode;
 1979                                             IF NOT SymTab.BoolCheck(t) THEN
 1980                                               SemError(214) END;
 1981                                             QbeGen.Jnz(q, lEnd, lTop);
 1982                                             QbeGen.EmitLabel(lEnd); .) .
 1983    LoopStat                              (. VAR lTop, lEnd: QbeGen.QVal; astNode: AST.Node; .)
 1984      = "LOOP"                            (. QbeGen.NewLabel(lTop);
 1985                                                    astStmt := AST.NoNode;
 1986                                             QbeGen.NewLabel(lEnd);
 1987                                             QbeGen.PushLoop(lEnd);
 1988                                             QbeGen.EmitLabel(lTop); .)
 1989        [ StatSeq ]
 1990        "END"                             (. astNode := AST.MakeNode(AST.NkLoop);
 1991                                             AST.SetChild(astNode, 0, astStmt);
 1992                                             astStmt := astNode;
 1993                                             QbeGen.Jmp(lTop);
 1994                                             QbeGen.PopLoop;
 1995                                             QbeGen.EmitLabel(lEnd); .) .
 1996    (* FOR with static-sign BY (literal, non-zero; 220 otherwise).
 1997       Runtime direction would need a compare-select; the literal
 1998       sign picks cslew/csegew at "DO" time. *)
 1999    ForStat                               (. VAR lv: SymTab.Name;
 2000                                               tlo, thi, tby:
 2001                                                 SymTab.TypeIndex;
 2002                                               qlo, qhi, qby, qt, qk, qb:
 2003                                                 QbeGen.QVal;
 2004                                               lTop, lBody, lEnd:
 2005                                                 QbeGen.QVal;
 2006                                               by: INTEGER;
 2007                                               ok: BOOLEAN;
 2008                                               astVar, astLo, astHi, astBy,
 2009                                               astNode: AST.Node; .)
 2010      = "FOR"                             (. by := 1; .)
 2011        GetIdent<lv> (. astVar := AST.MakeLeaf(AST.NkIdent, lv);
 2012                                             astStmt := AST.NoNode;
 2013                                             astBy := AST.NoNode;
 2014                                             ok := SymTab.Lookup(lv);
 2015                                             IF NOT ok THEN
 2016                                               SemError(201)
 2017                                             ELSIF (SymTab.SymKind(lv) #
 2018                                                    SymTab.KindVar)
 2019   AND (SymTab.SymKind(lv) #
 2020                                                   SymTab.KindParam) THEN
 2021                                               SemError(220); ok := FALSE
 2022                                             ELSIF NOT SymTab.IsIntFamily(
 2023                                                     SymTab.SymType(lv)) THEN
 2024                                               SemError(220); ok := FALSE
 2025                                             END; .)
 2026        ":=" Expr<tlo, qlo> (. astLo := astCur;
 2027                                             IF NOT SymTab.IsIntFamily(tlo) THEN
 2028                                               SemError(220); ok := FALSE
 2029                                             END; .)
 2030        "TO" Expr<thi, qhi> (. astHi := astCur;
 2031                                             IF NOT SymTab.IsIntFamily(thi) THEN
 2032                                               SemError(220); ok := FALSE
 2033                                             END; .)
 2034        [ "BY" Expr<tby, qby> (. astBy := astCur;
 2035                                             IF (tby #
 2036                                               SymTab.InvalidType)
 2037   AND NOT SymTab.IsIntFamily(tby) THEN
 2038                                               SemError(220); ok := FALSE
 2039                                             END;
 2040                                             IF NOT SymTab.ConstInt(qby, by) THEN
 2041                                               SemError(230); by := 1
 2042                                             ELSIF by = 0 THEN
 2043                                               SemError(220); by := 1
 2044                                             END; .) ]
 2045        "DO"                              (. IF ok THEN
 2046                                               QbeGen.StoreVar(lv, qlo,
 2047                                                 FALSE) END;
 2048                                             QbeGen.NewLabel(lTop);
 2049                                             QbeGen.NewLabel(lBody);
 2050                                             QbeGen.NewLabel(lEnd);
 2051                                             QbeGen.EmitLabel(lTop);
 2052                                             QbeGen.LoadVar(lv, FALSE, qt);
 2053                                             QbeGen.NewTemp(qk);
 2054                                             IF by > 0 THEN
 2055                                               QbeGen.Op3("cslew", qk,
 2056                                                 qt, qhi, FALSE)
 2057                                             ELSE QbeGen.Op3("csgew", qk,
 2058                                               qt, qhi, FALSE)
 2059                                             END;
 2060                                             QbeGen.Jnz(qk, lBody, lEnd);
 2061                                             QbeGen.EmitLabel(lBody); .)
 2062        [ StatSeq ]
 2063        "END" (. astNode := AST.MakeNode(AST.NkFor);
 2064                                             AST.SetChild(astNode, 0, astVar);
 2065                                             AST.SetChild(astNode, 1, astLo);
 2066                                             AST.SetChild(astNode, 2, astHi);
 2067                                             AST.SetChild(astNode, 3, astBy);
 2068                                             AST.SetChild(astNode, 4, astStmt);
 2069                                             astStmt := astNode;
 2070                                             IF ok THEN
 2071                                               QbeGen.LoadVar(lv, FALSE,
 2072                                                 qt);
 2073                                               QbeGen.IntStr(by, qb);
 2074                                               QbeGen.NewTemp(qk);
 2075                                               QbeGen.Op3("add", qk,
 2076                                                 qt, qb, FALSE);
 2077                                               QbeGen.StoreVar(lv, qk,
 2078                                                 FALSE) END;
 2079                                             QbeGen.Jmp(lTop);
 2080                                             QbeGen.EmitLabel(lEnd); .) .
 2081    CaseStat                              (. VAR tsel: SymTab.TypeIndex;
 2082                                               qsel, lEnd: QbeGen.QVal;
 2083                                               arm, astNode, astArms,
 2084                                               astArmsTail: AST.Node; .)
 2085      = "CASE" Expr<tsel, qsel>           (. astNode := AST.MakeNode(AST.NkCase);
 2086                                             AST.SetChild(astNode, 0, astCur);
 2087                                             astArms := AST.NoNode;
 2088                                             astArmsTail := AST.NoNode;
 2089                                             QbeGen.NewLabel(lEnd); .)
 2090        "OF" CaseAlt<tsel, qsel, lEnd, astArms, astArmsTail>
 2091        { "|" CaseAlt<tsel, qsel, lEnd, astArms, astArmsTail> }
 2092        [ "ELSE"                          (. astStmt := AST.NoNode; .)
 2093          [ StatSeq ]                     (. arm := AST.MakeNode(AST.NkCaseArm);
 2094                                             AST.SetOp(arm, 1);
 2095                                             AST.SetChild(arm, 0, astStmt);
 2096                                             AstAppend(AST.NkBlock,
 2097                                               astArms, astArmsTail, arm); .) ]
 2098        "END"                             (. AST.SetChild(astNode, 1, astArms);
 2099                                             astStmt := astNode;
 2100                                             QbeGen.EmitLabel(lEnd); .) .
 2101    (* Compare-chain lowering: each alternative ends its match-tests
 2102       with "jmp lAfter", so the no-match fallthrough skips the body:
 2103       "cmp; jnz(lBody,lF); lF: ... ; jmp lAfter; lBody: S; jmp lEnd;
 2104       lAfter:". Falls into the next alternative, ELSE, or END. *)
 2105    CaseAlt<tsel: SymTab.TypeIndex; qsel: QbeGen.QVal;
 2106            lEnd: QbeGen.QVal; VAR arms, armsTail: AST.Node>
 2107                                          (. VAR lBody, lAfter: QbeGen.QVal;
 2108                                               arm: AST.Node; .)
 2109      =                                   (. arm := AST.MakeNode(AST.NkCaseArm);
 2110                                             QbeGen.NewLabel(lBody);
 2111                                             QbeGen.NewLabel(lAfter); .)
 2112        CaseLabel<tsel, qsel, lBody, arm>
 2113        { "," CaseLabel<tsel, qsel, lBody, arm> }
 2114        ":"                               (. astStmt := AST.NoNode;
 2115                                             QbeGen.Jmp(lAfter);
 2116                                             QbeGen.EmitLabel(lBody); .)
 2117        [ StatSeq ]                       (. AST.SetChild(arm, AST.NChild(arm),
 2118                                             astStmt);
 2119                                             AstAppend(AST.NkBlock,
 2120                                               arms, armsTail, arm);
 2121                                             QbeGen.Jmp(lEnd);
 2122                                             QbeGen.EmitLabel(lAfter); .) .
 2123    CaseLabel<tsel: SymTab.TypeIndex; qsel: QbeGen.QVal;
 2124              lBody: QbeGen.QVal; arm: AST.Node>
 2125                                          (. VAR t2, t3: SymTab.TypeIndex;
 2126                                               q2, q3, qc, qd, qe:
 2127                                                 QbeGen.QVal;
 2128                                               astLab: AST.Node;
 2129                                               lNext: QbeGen.QVal; .)
 2130      = Expr<t2, q2> (. astLab := astCur;
 2131                                             IF (t2 #
 2132                                               SymTab.InvalidType)
 2133   AND (tsel #
 2134                                                 SymTab.InvalidType)
 2135   AND ((SymTab.ClassOf(t2) =
 2136                                                  SymTab.ClSet)
 2137                                                 OR (SymTab.ClassOf(tsel) =
 2138                                                     SymTab.ClSet)) THEN
 2139                                               SemError(230)
 2140                                             ELSIF (t2 #
 2141                                               SymTab.InvalidType)
 2142   AND (tsel #
 2143                                                 SymTab.InvalidType)
 2144   AND NOT SymTab.EqCheck(t2,
 2145                                                   tsel) THEN
 2146                                               SemError(213) END;
 2147                                             IF NOT QbeGen.IsImm(q2) THEN
 2148                                               SemError(230);
 2149                                               QbeGen.CopyOp("0", q2)
 2150                                             END;
 2151                                             QbeGen.NewLabel(lNext);
 2152                                             QbeGen.Cmp(SymTab.OpEq,
 2153                                               qsel, q2, qc, FALSE);
 2154                                             QbeGen.Jnz(qc, lBody, lNext);
 2155                                             QbeGen.EmitLabel(lNext); .)
 2156        [ ".." Expr<t3, q3>               (. astLab := AST.MakeBin(
 2157                                               AST.NkSubrange, 0, astLab, astCur);
 2158                                             IF (t3 #
 2159                                               SymTab.InvalidType)
 2160   AND (tsel #
 2161                                                 SymTab.InvalidType)
 2162   AND NOT SymTab.EqCheck(t3,
 2163                                                   tsel) THEN
 2164                                               SemError(213) END;
 2165                                             IF NOT QbeGen.IsImm(q3) THEN
 2166                                               SemError(230);
 2167                                               QbeGen.CopyOp("0", q3)
 2168                                             END;
 2169                                             QbeGen.Cmp(SymTab.OpGe,
 2170                                               qsel, q2, qc, FALSE);
 2171                                             QbeGen.Cmp(SymTab.OpLe,
 2172                                               qsel, q3, qd, FALSE);
 2173                                             QbeGen.NewTemp(qe);
 2174                                             QbeGen.Op3("and", qe, qc, qd,
 2175                                               FALSE);
 2176                                             QbeGen.NewLabel(lNext);
 2177                                             QbeGen.Jnz(qe, lBody, lNext);
 2178                                             QbeGen.EmitLabel(lNext); .) ]
 2179                                          (. AST.SetChild(arm,
 2180                                               AST.NChild(arm), astLab); .) .
 2181    ReturnStat                            (. VAR t: SymTab.TypeIndex;
 2182                                               q, qt: QbeGen.QVal;
 2183                                               res: SymTab.TypeIndex;
 2184                                               hadE, conv: BOOLEAN;
 2185                                               astVal, astNode: AST.Node; .)
 2186      = "RETURN"                          (. hadE := FALSE; astStmt := AST.NoNode; .)
 2187        [ Expr<t, q> (. hadE := TRUE; astVal := astCur; .) ]
 2188                                          (. astNode := AST.MakeNode(AST.NkReturn);
 2189                                             IF hadE THEN
 2190                                               AST.SetChild(astNode, 0, astVal)
 2191                                             END;
 2192                                             astStmt := astNode;
 2193                                             conv := FALSE;
 2194                                             IF NOT SymTab.InProc() THEN
 2195                                               SemError(232)
 2196                                             ELSE res := SymTab.CurRes();
 2197                                               IF NOT hadE THEN
 2198                                                 IF res #
 2199                                                    SymTab.InvalidType THEN
 2200                                                   SemError(232)
 2201                                                 ELSE QbeGen.EmitRet(q,
 2202                                                   FALSE)
 2203                                                 END
 2204                                               ELSIF (res =
 2205                                                      SymTab.InvalidType)
 2206                                                  OR (t #
 2207                                                      SymTab.InvalidType)
 2208   AND NOT SymTab.Assignable(t,
 2209                                                       res) THEN
 2210                                                 SemError(232)
 2211                                               ELSE
 2212                                                 conv := (SymTab.ClassOf(
 2213                                                   res) = SymTab.ClReal)
 2214   AND SymTab.IsIntFamily(t);
 2215                                                 IF conv THEN
 2216                                                   QbeGen.ConvIR(q, qt);
 2217                                                   QbeGen.EmitRet(qt, TRUE)
 2218                                                 ELSE QbeGen.EmitRet(q, TRUE)
 2219                                                 END
 2220                                               END
 2221                                             END; .) .
 2222    HaltStat                              (. VAR t: SymTab.TypeIndex;
 2223                                               q: QbeGen.QVal;
 2224                                               astVal, astNode: AST.Node; .)
 2225      = "HALT" (. astVal := AST.NoNode; .)
 2226        [ "(" Expr<t, q> (. astVal := astCur; .) ")" ]
 2227                                          (. astNode := AST.MakeNode(AST.NkHalt);
 2228                                             IF astVal # AST.NoNode THEN
 2229                                               AST.SetChild(astNode, 0, astVal)
 2230                                             END;
 2231                                             astStmt := astNode;
 2232                                             QbeGen.HaltQ; .) .
 2233    (* Designator: scalar loads, array addresses, and index suffixes.
 2234       Each index descends one level (bounds-checked, trap on breach);
 2235       nested levels reload the inner descriptor address. q ends as the
 2236       value (scalars), the descriptor address (plain arrays), or the
 2237       element address (indexed); sfx marks the indexed form. *)
 2238    Design<VAR t: SymTab.TypeIndex; VAR k: INTEGER;
 2239           VAR q: QbeGen.QVal; VAR qn: SymTab.Name; VAR sfx: BOOLEAN>
 2240                                          (. VAR n, fn, mal: SymTab.Name;
 2241                                               cls: INTEGER;
 2242                                               ic: SymTab.TypeIndex;
 2243                                               curT, it, eT, bt:
 2244                                                 SymTab.TypeIndex;
 2245                                               iq, ql, qlo, qhi, qe:
 2246                                                 QbeGen.QVal;
 2247                                               lo, hi: INTEGER;
 2248                                               fo: INTEGER;
 2249                                               isOpen: BOOLEAN;
 2250                                               qb, cv: QbeGen.QVal;
 2251                                               fid, fref, slot: INTEGER;
 2252                                               r: BOOLEAN;
 2253                                                astDes, astSel: AST.Node; .)
 2254      = GetIdent<n>                       (. methCls := SymTab.InvalidType;
 2255                                             QbeGen.CopyOp(n, qn);
 2256                                             sfx := FALSE;
 2257                                             fid := 0; fref := 0; slot := 0;
 2258                                             IF NOT SymTab.Lookup(n) THEN
 2259                                               (* a bare method name inside
 2260                                                  a CLASS IMPLEMENTATION
 2261                                                  is a sibling call on
 2262                                                  THIS *)
 2263                                               ic := SymTab.CurImplClass();
 2264                                               IF (ic #
 2265                                                  SymTab.InvalidType)
 2266    AND SymTab.MethodExists(ic, n) THEN
 2267                                                 sfx := FALSE;
 2268                                                 QbeGen.ThisBase(q);
 2269                                                 QbeGen.ArmRecv(q);
 2270                                                 methCls := ic;
 2271                                                 k := SymTab.KindProc;
 2272                                                 t := SymTab.InvalidType
 2273                                               ELSIF SymTab.InProc() THEN
 2274                                                 (* not declared yet: a
 2275                                                    forward reference to a
 2276                                                    module-level variable
 2277                                                    declared further down. *)
 2278                                                 k := SymTab.KindVar;
 2279                                                 r := SymTab.FwdVarRef(n, k,
 2280                                                   fref, t);
 2281                                                 slot := QbeGen.FwdDesignator();
 2282                                                 FwdVarNote(fref, slot);
 2283                                                 fid := slot;
 2284                                                 QbeGen.FwdAddrOper(fid, q);
 2285                                                 sfx := TRUE
 2286                                               ELSE
 2287                                                 SemError(201);
 2288                                                 t :=
 2289                                                   SymTab.InvalidType;
 2290                                                 k := -1;
 2291                                                 QbeGen.CopyOp("0", q)
 2292                                               END
 2293                                             ELSE
 2294                                               t := SymTab.SymType(n);
 2295                                               k := SymTab.SymKind(n);
 2296                                               IF k = SymTab.KindConst THEN
 2297                                                 IF SymTab.Equal(n,
 2298                                                    "TRUE") THEN
 2299                                                   t := SymTab.BoolType();
 2300                                                   QbeGen.CopyOp("1", q)
 2301                                                 ELSIF SymTab.Equal(n,
 2302                                                    "FALSE") THEN
 2303                                                   t := SymTab.BoolType();
 2304                                                   QbeGen.CopyOp("0", q)
 2305                                                 ELSIF SymTab.Equal(n,
 2306                                                    "NIL") THEN
 2307                                                   QbeGen.CopyOp("0", q)
 2308                                                 ELSE
 2309                                                   cls :=
 2310                                                     SymTab.ClassOf(t);
 2311                                                   IF (t #
 2312                                                       SymTab.InvalidType)
 2313   AND ((cls = SymTab.ClInt)
 2314                                                      OR (cls
 2315                                                          = SymTab.ClChar)
 2316                                                      OR (cls
 2317                                                          = SymTab.ClEnum)
 2318                                                      OR (cls
 2319                                                          = SymTab.ClReal)
 2320                                                      OR (cls
 2321                                                          = SymTab.ClLong)
 2322                                                      OR (cls
 2323                                                          = SymTab.ClNil)) THEN
 2324                                                     IF cls = SymTab.ClNil THEN
 2325                                                       QbeGen.CopyOp("0", q)
 2326                                                     ELSIF ((cls
 2327                                                         = SymTab.ClInt)
 2328                                                       OR (cls
 2329                                                         = SymTab.ClChar)
 2330                                                       OR (cls
 2331                                                         = SymTab.ClEnum)
 2332                                                       OR (cls
 2333                                                         = SymTab.ClLong))
 2334    AND SymTab.GetSymVal(n, cv)
 2335    AND QbeGen.IsImm(cv) THEN
 2336                                                       QbeGen.CopyOp(cv, q)
 2337                                                     ELSE
 2338                                                       QbeGen.LoadVar(n,
 2339                                                         cls = SymTab.ClReal,
 2340                                                         q)
 2341                                                     END
 2342                                                   ELSIF (cls = SymTab.ClArray)
 2343                                                      OR (cls = SymTab.ClRecord)
 2344                                                      OR (cls = SymTab.ClClass)
 2345                                                      OR (cls = SymTab.ClStr)
 2346                                                      OR (cls = SymTab.ClUStr) THEN
 2347                                                     (* aggregate constant:
 2348                                                        its value IS the
 2349                                                        descriptor address *)
 2350                                                     IF SymTab.GetSymVal(n, cv) THEN
 2351                                                       QbeGen.CopyOp(cv, q)
 2352                                                     ELSE
 2353                                                       QbeGen.CopyOp("0", q)
 2354                                                     END
 2355                                                   ELSE
 2356                                                     IF t #
 2357                                                        SymTab.InvalidType THEN
 2358                                                       SemError(230)
 2359                                                     END;
 2360                                                     QbeGen.CopyOp("0", q)
 2361                                                   END
 2362                                                 END
 2363                                               ELSIF (k = SymTab.KindVar)
 2364                                                  OR (k = SymTab.KindParam) THEN
 2365                                                 cls :=
 2366                                                   SymTab.ClassOf(t);
 2367                                                 IF (cls = SymTab.ClInt)
 2368                                                    OR (cls = SymTab.ClBool)
 2369                                                    OR (cls = SymTab.ClChar)
 2370                                                    OR (cls = SymTab.ClUChar)
 2371                                                    OR (cls = SymTab.ClEnum)
 2372                                                    OR (cls
 2373                                                        = SymTab.ClReal) THEN
 2374                                                   QbeGen.LoadVar(n,
 2375                                                     cls = SymTab.ClReal, q)
 2376                                                 ELSIF (cls = SymTab.ClPtr)
 2377                                                    OR (cls = SymTab.ClProc) THEN
 2378                                                   QbeGen.LoadPtr(n, q)
 2379                                                 ELSIF cls = SymTab.ClLong THEN
 2380                                                   QbeGen.LoadLong(n, q)
 2381                                                 ELSIF (cls
 2382                                                         = SymTab.ClArray)
 2383                                                    OR (cls
 2384                                                        = SymTab.ClSet)
 2385                                                    OR (cls
 2386                                                        = SymTab.ClRecord)
 2387                                                    OR (cls
 2388                                                        = SymTab.ClUStr)
 2389                                                    OR (cls
 2390                                                        = SymTab.ClClass) THEN
 2391                                                   QbeGen.AddrOf(n, q)
 2392                                                 ELSE SemError(230);
 2393                                                   QbeGen.CopyOp("0", q)
 2394                                                 END
 2395                                               ELSE QbeGen.CopyOp("0", q);
 2396                                                 IF k = SymTab.KindImport THEN
 2397                                                   SemError(230)
 2398                                                 ELSIF k =
 2399                                                    SymTab.KindProc THEN
 2400                                                   (* bare procedure name:
 2401                                                      a following ArgList
 2402                                                      makes it a call;
 2403                                                      otherwise Fact
 2404                                                      reports 230 *)
 2405                                                 ELSE
 2406                                                   IF k = SymTab.KindField THEN
 2407                                                     IF QbeGen.TopWith(qb) THEN
 2408                                                       fo :=
 2409                                                         SymTab.FieldOffset(
 2410                                                         SymTab.FieldOwner(n),
 2411                                                         n);
 2412                                                       QbeGen.FieldAddr(qb,
 2413                                                         fo, q);
 2414                                                       sfx := TRUE
 2415                                                     ELSE SemError(230);
 2416                                                       QbeGen.CopyOp("0", q)
 2417                                                     END
 2418                                                   END
 2419                                                 END
 2420                                               END
 2421                                             END; .)
 2422        (. astDes := AST.MakeNode(AST.NkDesignator);
 2423           AST.SetChild(astDes, AST.NChild(astDes), AST.MakeLeaf(AST.NkIdent, n)); .)
 2424        { "[" Expr<it, iq>
 2425                                          (. AST.SetChild(astDes, AST.NChild(astDes),
 2426               AST.MakeUn(AST.NkSelector, AST.SelIndex, astCur)); IF t = SymTab.InvalidType THEN
 2427                                             ELSIF SymTab.ClassOf(t) #
 2428                                                   SymTab.ClArray THEN
 2429                                               SemError(217);
 2430                                               t := SymTab.InvalidType
 2431                                             ELSIF NOT SymTab.IsIntFamily(it)
 2432   AND (SymTab.ClassOf(it) #
 2433                                                   SymTab.ClChar)
 2434   AND (SymTab.ClassOf(it) #
 2435                                                   SymTab.ClEnum) THEN
 2436                                               SemError(218);
 2437                                               t := SymTab.InvalidType
 2438                                             ELSE
 2439                                               QbeGen.WidenIndex(iq, ql);
 2440                                               isOpen :=
 2441                                                 SymTab.IsOpenArray(t);
 2442                                               IF isOpen THEN
 2443                                                 QbeGen.CopyOp("0", qlo);
 2444                                                 IF SymTab.IsCharArray(t)
 2445    OR SymTab.IsUCharArray(t) THEN
 2446                                                   QbeGen.OpenHiChar(q, qhi)
 2447                                                 ELSE QbeGen.OpenHi(q, qhi)
 2448                                                 END
 2449                                               ELSE
 2450                                                 lo := SymTab.ArrayLo(t);
 2451                                                 hi := SymTab.ArrayHi(t);
 2452                                                 IF SymTab.IsCharArray(t)
 2453    OR SymTab.IsUCharArray(t) THEN
 2454                                                   hi := hi + 1
 2455                                                 END;
 2456                                                 QbeGen.IntStr(lo, qlo);
 2457                                                 QbeGen.IntStr(hi, qhi)
 2458                                               END;
 2459                                               QbeGen.CheckRange(ql, qlo,
 2460                                                 qhi);
 2461                                               eT := SymTab.ArrayElem(t);
 2462                                               QbeGen.ElemAddr(q, ql, qlo,
 2463                                                 t, qe);
 2464                                               IF SymTab.ClassOf(eT) =
 2465                                                  SymTab.ClArray THEN
 2466                                                 QbeGen.ElemLoad(qe, eT, q)
 2467                                               ELSE QbeGen.CopyOp(qe, q)
 2468                                               END;
 2469                                               t := eT; sfx := TRUE
 2470                                             END; .)
 2471          { "," Expr<it, iq>
 2472                                          (. AST.SetChild(astDes, AST.NChild(astDes),
 2473               AST.MakeUn(AST.NkSelector, AST.SelIndex, astCur)); IF t = SymTab.InvalidType THEN
 2474                                             ELSIF SymTab.ClassOf(t) #
 2475                                                   SymTab.ClArray THEN
 2476                                               SemError(217);
 2477                                               t := SymTab.InvalidType
 2478                                             ELSIF NOT SymTab.IsIntFamily(it)
 2479   AND (SymTab.ClassOf(it) #
 2480                                                   SymTab.ClChar)
 2481   AND (SymTab.ClassOf(it) #
 2482                                                   SymTab.ClEnum) THEN
 2483                                               SemError(218);
 2484                                               t := SymTab.InvalidType
 2485                                             ELSE
 2486                                               QbeGen.WidenIndex(iq, ql);
 2487                                               isOpen :=
 2488                                                 SymTab.IsOpenArray(t);
 2489                                               IF isOpen THEN
 2490                                                 QbeGen.CopyOp("0", qlo);
 2491                                                 IF SymTab.IsCharArray(t)
 2492    OR SymTab.IsUCharArray(t) THEN
 2493                                                   QbeGen.OpenHiChar(q, qhi)
 2494                                                 ELSE QbeGen.OpenHi(q, qhi)
 2495                                                 END
 2496                                               ELSE
 2497                                                 lo := SymTab.ArrayLo(t);
 2498                                                 hi := SymTab.ArrayHi(t);
 2499                                                 IF SymTab.IsCharArray(t)
 2500    OR SymTab.IsUCharArray(t) THEN
 2501                                                   hi := hi + 1
 2502                                                 END;
 2503                                                 QbeGen.IntStr(lo, qlo);
 2504                                                 QbeGen.IntStr(hi, qhi)
 2505                                               END;
 2506                                               QbeGen.CheckRange(ql, qlo,
 2507                                                 qhi);
 2508                                               eT := SymTab.ArrayElem(t);
 2509                                               QbeGen.ElemAddr(q, ql, qlo,
 2510                                                 t, qe);
 2511                                               IF SymTab.ClassOf(eT) =
 2512                                                  SymTab.ClArray THEN
 2513                                                 QbeGen.ElemLoad(qe, eT, q)
 2514                                               ELSE QbeGen.CopyOp(qe, q)
 2515                                               END;
 2516                                               t := eT; sfx := TRUE
 2517                                             END; .) }
 2518          "]"
 2519        | "." GetIdent<fn>
 2520                                          (. astSel := AST.MakeNode(AST.NkSelector);
 2521               AST.SetOp(astSel, AST.SelField);
 2522               AST.SetChild(astSel, 0, AST.MakeLeaf(AST.NkIdent, fn));
 2523               AST.SetChild(astDes, AST.NChild(astDes), astSel); IF k = SymTab.KindModule THEN
 2524                                               (* qualified L.x: materialize
 2525                                                  the export, then load it *)
 2526                                               IF NOT SymTab.MaterializeAlias(n,
 2527                                                    fn, mal) THEN
 2528                                                 SemError(201);
 2529                                                 t := SymTab.InvalidType;
 2530                                                 QbeGen.CopyOp("0", q)
 2531                                               ELSE
 2532                                                 QbeGen.CopyOp(mal, qn);
 2533                                                 t := SymTab.SymType(mal);
 2534                                                 k := SymTab.SymKind(mal);
 2535                                                 sfx := FALSE;
 2536                                                 IF k = SymTab.KindProc THEN
 2537                                                   (* call: ArgList supplies
 2538                                                      the value *)
 2539                                                   QbeGen.CopyOp("0", q)
 2540                                                 ELSIF NOT QbeGen.LoadDesignator(
 2541                                                      mal, t, k, q) THEN
 2542                                                   SemError(230);
 2543                                                   QbeGen.CopyOp("0", q)
 2544                                                 END
 2545                                               END
 2546                                             ELSIF t = SymTab.InvalidType THEN
 2547                                             ELSIF (SymTab.ClassOf(t) #
 2548                                                    SymTab.ClRecord)
 2549   AND (SymTab.ClassOf(t) #
 2550                                                   SymTab.ClClass) THEN
 2551                                               SemError(215);
 2552                                               t := SymTab.InvalidType
 2553                                             ELSIF (SymTab.ClassOf(t) =
 2554                                                    SymTab.ClClass)
 2555    AND SymTab.MethodExists(t, fn) THEN
 2556                                               (* obj.Method: bind the
 2557                                                  method and pass obj as
 2558                                                  the hidden receiver; q
 2559                                                  already holds the
 2560                                                  object's address *)
 2561                                               QbeGen.ArmRecv(q);
 2562                                               QbeGen.CopyOp(fn, n);
 2563                                               QbeGen.CopyOp(fn, qn);
 2564                                               methCls := t;
 2565                                               k := SymTab.KindProc;
 2566                                               t := SymTab.InvalidType
 2567                                             ELSIF NOT SymTab.FieldExists(t,
 2568                                                      fn) THEN
 2569                                               SemError(216);
 2570                                               t := SymTab.InvalidType
 2571                                             ELSE
 2572                                               fo := SymTab.FieldOffset(t,
 2573                                                 fn);
 2574                                               t := SymTab.FieldType(t, fn);
 2575                                               QbeGen.FieldAddr(q, fo, qe);
 2576                                               (* array fields are inline:
 2577                                                  the field address is the
 2578                                                  descriptor, like records *)
 2579                                               QbeGen.CopyOp(qe, q);
 2580                                               sfx := TRUE
 2581                                             END; .)
 2582        | "^"
 2583                                          (. astSel := AST.MakeNode(AST.NkSelector);
 2584               AST.SetOp(astSel, AST.SelDeref);
 2585               AST.SetChild(astDes, AST.NChild(astDes), astSel); IF t = SymTab.InvalidType THEN
 2586                                             ELSIF SymTab.ClassOf(t) #
 2587                                                   SymTab.ClPtr THEN
 2588                                               SemError(219);
 2589                                               t := SymTab.InvalidType
 2590                                             ELSE
 2591                                               bt := SymTab.PtrBase(t);
 2592                                               IF bt = SymTab.InvalidType THEN
 2593                                               ELSE
 2594                                                 IF sfx THEN
 2595                                                   QbeGen.ElemLoad(q, t,
 2596                                                     qb);
 2597                                                   QbeGen.CopyOp(qb, q)
 2598                                                 END;
 2599                                                 t := bt;
 2600                                                 (* q holds the pointee
 2601                                                    address: Fact loads
 2602                                                    scalars/pointers and uses
 2603                                                    the address for
 2604                                                    aggregates; the VAR-actual
 2605                                                    note is q itself. *)
 2606                                                 sfx := TRUE
 2607                                               END
 2608                                             END; .) } (. astCur := astDes; .) .
 2609    (* Result suffix (ISO component after a function call): `F()^`,
 2610       `F()[i]`, `F().field`.  The call result is in t/q with sfx FALSE
 2611       (a value, or a descriptor address for aggregates); each component
 2612       descends one level exactly like the Design components. *)
 2613    ResultComp<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal;
 2614               VAR sfx: BOOLEAN; VAR node: AST.Node>          (. VAR it, eT, bt: SymTab.TypeIndex;
 2615                                               iq, ql, qlo, qhi, qe, qb:
 2616                                                 QbeGen.QVal;
 2617                                               lo, hi, fo: INTEGER;
 2618                                               isOpen: BOOLEAN;
 2619                                               fname: SymTab.Name;
 2620                                               astWrap, astSel: AST.Node; .)
 2621      = "[" Expr<it, iq>
 2622                                          (. IF AST.Kind(node) # AST.NkDesignator THEN
 2623                                               astWrap := AST.MakeNode(
 2624                                                 AST.NkDesignator);
 2625                                               AST.SetChild(astWrap, 0, node);
 2626                                               node := astWrap
 2627                                             END;
 2628                                             AST.SetChild(node, AST.NChild(node),
 2629                                               AST.MakeUn(AST.NkSelector,
 2630                                                 AST.SelIndex, astCur)); IF t = SymTab.InvalidType THEN
 2631                                             ELSIF SymTab.ClassOf(t) #
 2632                                                   SymTab.ClArray THEN
 2633                                               SemError(217);
 2634                                               t := SymTab.InvalidType
 2635                                             ELSIF NOT SymTab.IsIntFamily(it)
 2636    AND (SymTab.ClassOf(it) # SymTab.ClChar)
 2637    AND (SymTab.ClassOf(it) # SymTab.ClEnum) THEN
 2638                                               SemError(218);
 2639                                               t := SymTab.InvalidType
 2640                                             ELSE
 2641                                               QbeGen.WidenIndex(iq, ql);
 2642                                               isOpen :=
 2643                                                 SymTab.IsOpenArray(t);
 2644                                               IF isOpen THEN
 2645                                                 QbeGen.CopyOp("0", qlo);
 2646                                                 IF SymTab.IsCharArray(t)
 2647    OR SymTab.IsUCharArray(t) THEN
 2648                                                   QbeGen.OpenHiChar(q, qhi)
 2649                                                 ELSE QbeGen.OpenHi(q, qhi)
 2650                                                 END
 2651                                               ELSE
 2652                                                 lo := SymTab.ArrayLo(t);
 2653                                                 hi := SymTab.ArrayHi(t);
 2654                                                 IF SymTab.IsCharArray(t)
 2655    OR SymTab.IsUCharArray(t) THEN
 2656                                                   hi := hi + 1
 2657                                                 END;
 2658                                                 QbeGen.IntStr(lo, qlo);
 2659                                                 QbeGen.IntStr(hi, qhi)
 2660                                               END;
 2661                                               QbeGen.CheckRange(ql, qlo,
 2662                                                 qhi);
 2663                                               eT := SymTab.ArrayElem(t);
 2664                                               QbeGen.ElemAddr(q, ql, qlo,
 2665                                                 t, qe);
 2666                                               IF SymTab.ClassOf(eT) =
 2667                                                  SymTab.ClArray THEN
 2668                                                 QbeGen.ElemLoad(qe, eT, q)
 2669                                               ELSE QbeGen.CopyOp(qe, q)
 2670                                               END;
 2671                                               t := eT; sfx := TRUE
 2672                                             END; .)
 2673        "]"
 2674      | "." GetIdent<fname>
 2675                                          (. IF AST.Kind(node) # AST.NkDesignator THEN
 2676                                               astWrap := AST.MakeNode(
 2677                                                 AST.NkDesignator);
 2678                                               AST.SetChild(astWrap, 0, node);
 2679                                               node := astWrap
 2680                                             END;
 2681                                             AST.SetChild(node, AST.NChild(node),
 2682                                               AST.MakeUn(AST.NkSelector,
 2683                                                 AST.SelField,
 2684                                                 AST.MakeLeaf(AST.NkIdent,
 2685                                                   fname))); IF t = SymTab.InvalidType THEN
 2686                                             ELSIF (SymTab.ClassOf(t) #
 2687                                                    SymTab.ClRecord)
 2688    AND (SymTab.ClassOf(t) # SymTab.ClClass) THEN
 2689                                               SemError(215);
 2690                                               t := SymTab.InvalidType
 2691                                             ELSIF NOT SymTab.FieldExists(t,
 2692                                                      fname) THEN
 2693                                               SemError(216);
 2694                                               t := SymTab.InvalidType
 2695                                             ELSE
 2696                                               fo := SymTab.FieldOffset(t,
 2697                                                 fname);
 2698                                               t := SymTab.FieldType(t, fname);
 2699                                               QbeGen.FieldAddr(q, fo, qe);
 2700                                               QbeGen.CopyOp(qe, q);
 2701                                               sfx := TRUE
 2702                                             END; .)
 2703      | "^"                               (. IF AST.Kind(node) # AST.NkDesignator THEN
 2704                                               astWrap := AST.MakeNode(
 2705                                                 AST.NkDesignator);
 2706                                               AST.SetChild(astWrap, 0, node);
 2707                                               node := astWrap
 2708                                             END;
 2709                                             astSel := AST.MakeNode(AST.NkSelector);
 2710                                             AST.SetOp(astSel, AST.SelDeref);
 2711                                             AST.SetChild(node,
 2712                                               AST.NChild(node), astSel); IF t = SymTab.InvalidType THEN
 2713                                             ELSIF SymTab.ClassOf(t) #
 2714                                                   SymTab.ClPtr THEN
 2715                                               SemError(219);
 2716                                               t := SymTab.InvalidType
 2717                                             ELSE
 2718                                               bt := SymTab.PtrBase(t);
 2719                                               IF bt # SymTab.InvalidType THEN
 2720                                                 IF sfx THEN
 2721                                                   QbeGen.ElemLoad(q, t, qb);
 2722                                                   QbeGen.CopyOp(qb, q)
 2723                                                 END;
 2724                                                 t := bt; sfx := TRUE
 2725                                               END
 2726                                             END; .) .
 2727    Expr<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal>
 2728                                          (. VAR t2: SymTab.TypeIndex;
 2729                                               op: INTEGER;
 2730                                               q2, qt, wl: QbeGen.QVal;
 2731                                                astA, astB: AST.Node;
 2732                                                astOp: INTEGER;
 2733                                                astMade: BOOLEAN;
 2734                                               isR: BOOLEAN; .)
 2735      = SimExpr<t, q>                     (. astA := astCur; astMade := FALSE; .)
 2736        [ Rel<op> SimExpr<t2, q2>
 2737          (. astB := astCur; astMade := TRUE;
 2738              astOp := AST.OpEq;
 2739              IF op = SymTab.OpNeq1 THEN astOp := AST.OpNe
 2740              ELSIF op = SymTab.OpNeq2 THEN astOp := AST.OpNe
 2741              ELSIF op = SymTab.OpLt THEN astOp := AST.OpLt
 2742              ELSIF op = SymTab.OpLe THEN astOp := AST.OpLe
 2743              ELSIF op = SymTab.OpGt THEN astOp := AST.OpGt
 2744              ELSIF op = SymTab.OpGe THEN astOp := AST.OpGe
 2745              ELSIF op = SymTab.OpIn THEN astOp := AST.OpIn
 2746              END;
 2747              IF op = SymTab.OpIn THEN
 2748               IF SymTab.InCheck(t, t2) THEN
 2749                 IF (t = SymTab.InvalidType)
 2750                    OR (t2 = SymTab.InvalidType) THEN
 2751                   t := SymTab.BoolType(); QbeGen.CopyOp("0", q)
 2752                 ELSE
 2753                   QbeGen.InSet(q, q2, SymTab.SetBaseLo(t2),
 2754                     SymTab.SetCount(t2), qt);
 2755                   t := SymTab.BoolType(); QbeGen.CopyOp(qt, q)
 2756                 END
 2757               ELSE SemError(222); t := SymTab.InvalidType;
 2758                 QbeGen.CopyOp("0", q)
 2759               END
 2760             ELSIF SymTab.RelCheck(t, t2, op) THEN
 2761               IF (t = SymTab.InvalidType)
 2762                  OR (t2 = SymTab.InvalidType) THEN
 2763                 t := SymTab.BoolType(); QbeGen.CopyOp("0", q)
 2764               ELSIF (SymTab.ClassOf(t) = SymTab.ClPtr)
 2765                  OR (SymTab.ClassOf(t2) = SymTab.ClPtr) THEN
 2766                 IF SymTab.IsFwdVar(t) OR SymTab.IsFwdVar(t2) THEN
 2767                   QbeGen.Cmp(op, q, q2, qt, FALSE);
 2768                   t := SymTab.BoolType(); QbeGen.CopyOp(qt, q)
 2769                 ELSIF (op # SymTab.OpEq) AND (op # SymTab.OpNeq1)
 2770   AND (op # SymTab.OpNeq2) THEN
 2771                   SemError(213); t := SymTab.InvalidType;
 2772                   QbeGen.CopyOp("0", q)
 2773                 ELSE
 2774                   QbeGen.CmpL(op, q, q2, qt);
 2775                   t := SymTab.BoolType(); QbeGen.CopyOp(qt, q)
 2776                 END
 2777               ELSIF (SymTab.ClassOf(t) = SymTab.ClSet)
 2778                  OR (SymTab.ClassOf(t2) = SymTab.ClSet) THEN
 2779                 QbeGen.CmpSet(op, q, q2,
 2780                   SymTab.SetWords(t), SymTab.SetWords(t2), qt);
 2781                 t := SymTab.BoolType(); QbeGen.CopyOp(qt, q)
 2782               ELSIF SymTab.StrCompat(t, t2) THEN
 2783                 QbeGen.StrEq(op, q, q2, qt);
 2784                 t := SymTab.BoolType(); QbeGen.CopyOp(qt, q)
 2785               ELSIF SymTab.IsLongFamily(t)
 2786                  OR SymTab.IsLongFamily(t2) THEN
 2787                 IF SymTab.IsIntFamily(t) THEN
 2788                   QbeGen.WidenLong(q, wl); QbeGen.CopyOp(wl, q)
 2789                 END;
 2790                 IF SymTab.IsIntFamily(t2) THEN
 2791                   QbeGen.WidenLong(q2, wl); QbeGen.CopyOp(wl, q2)
 2792                 END;
 2793                 QbeGen.CmpLong(op, q, q2, qt);
 2794                 t := SymTab.BoolType(); QbeGen.CopyOp(qt, q)
 2795               ELSE
 2796                 isR := SymTab.ClassOf(t) = SymTab.ClReal;
 2797                 t := SymTab.BoolType();
 2798                 QbeGen.Cmp(op, q, q2, qt, isR);
 2799                 QbeGen.CopyOp(qt, q)
 2800               END
 2801             ELSE SemError(213); t := SymTab.InvalidType;
 2802                QbeGen.CopyOp("0", q)
 2803              END;
 2804              astCur := AST.MakeBin(AST.NkBinExpr, astOp, astA, astB); .) ]
 2805         (. IF NOT astMade THEN astCur := astA END; .) .
 2806    Rel<VAR op: INTEGER>
 2807      = "="                               (. op := SymTab.OpEq; .)
 2808      | "#"                               (. op := SymTab.OpNeq1; .)
 2809      | "<"                               (. op := SymTab.OpLt; .)
 2810      | "<="                              (. op := SymTab.OpLe; .)
 2811      | ">"                               (. op := SymTab.OpGt; .)
 2812      | ">="                              (. op := SymTab.OpGe; .)
 2813      | "IN"                              (. op := SymTab.OpIn; .) .
 2814    SimExpr<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal>
 2815                                          (. VAR t2, res2, lt, rt:
 2816                                                 SymTab.TypeIndex;
 2817                                               op: INTEGER;
 2818                                               q2, qt, wq, qf, q2a, q2b:
 2819                                                 QbeGen.QVal;
 2820                                               neg, isR, isL, folded:
 2821                                                 BOOLEAN;
 2822                                               fok: BOOLEAN;
 2823                                               lw, rw, mw: CARDINAL;
 2824                                               lTrue, lNext, lDone, qr, qs: QbeGen.QVal;
 2825                                                astA, astB: AST.Node;
 2826                                                astSign, astOp: INTEGER; .)
 2827      =                                   (. neg := FALSE; astSign := 0; .)
 2828        [ "+"                         (. neg := TRUE; astSign := 1; .)
 2829        | "-"                         (. neg := TRUE; astSign := -1; .) ]
 2830        Term<t, q> (. astA := astCur; IF neg THEN
 2831                                             IF QbeGen.IsImm(q) THEN
 2832                                               QbeGen.NegFold(q, q)
 2833                                             ELSE QbeGen.NewTemp(qt);
 2834                                               QbeGen.NegQ(q, qt,
 2835                                                 SymTab.ClassOf(t)
 2836                                                 = SymTab.ClReal);
 2837                                               QbeGen.CopyOp(qt, q)
 2838                                             END
 2839                                           END;
 2840                                           IF astSign < 0 THEN
 2841                                             astCur := AST.MakeUn(
 2842                                               AST.NkUnary, AST.OpSub, astA);
 2843                                             astA := astCur
 2844                                           END; .)
 2845        { AddOp<op>                       (. IF op = SymTab.OpOr THEN
 2846                                               QbeGen.DelayBegin END; .)
 2847          Term<t2, q2> (. astB := astCur; IF op = SymTab.OpOr THEN
 2848                                               QbeGen.DelayEnd END; .)
 2849          (. astOp := AST.OpAdd;
 2850             IF op = SymTab.OpSub THEN astOp := AST.OpSub
 2851             ELSIF op = SymTab.OpOr THEN astOp := AST.OpOr END;
 2852             astA := AST.MakeBin(AST.NkBinExpr, astOp, astA, astB);
 2853             astCur := astA;
 2854             IF op = SymTab.OpOr THEN
 2855               (* short-circuit: if q is true the RHS is skipped *)
 2856               IF SymTab.BoolCheck(t) AND SymTab.BoolCheck(t2) THEN
 2857                 t := SymTab.BoolType()
 2858               ELSE SemError(212); t := SymTab.InvalidType END;
 2859               IF t # SymTab.InvalidType THEN
 2860                 QbeGen.Slot4(qs);
 2861                 QbeGen.NewLabel(lTrue);
 2862                 QbeGen.NewLabel(lNext);
 2863                 QbeGen.NewLabel(lDone);
 2864                 QbeGen.Jnz(q, lTrue, lNext);
 2865                 QbeGen.EmitLabel(lTrue);
 2866                 QbeGen.StoreW(qs, "1");
 2867                 QbeGen.Jmp(lDone);
 2868                 QbeGen.EmitLabel(lNext);
 2869                 QbeGen.DelayFlush;
 2870                 QbeGen.StoreW(qs, q2);
 2871                 QbeGen.Jmp(lDone);
 2872                 QbeGen.EmitLabel(lDone);
 2873                 QbeGen.LoadW(qs, qr);
 2874                 QbeGen.CopyOp(qr, q)
 2875               ELSE QbeGen.DelayFlush; QbeGen.CopyOp("0", q)
 2876               END
 2877             ELSIF (op = SymTab.OpAdd)
 2878               AND (SymTab.UStrCompat(t, t2)
 2879                 OR ((SymTab.ClassOf(t) = SymTab.ClUChar)
 2880                   AND (SymTab.ClassOf(t2) = SymTab.ClUStr))
 2881                 OR ((SymTab.ClassOf(t) = SymTab.ClUStr)
 2882                   AND (SymTab.ClassOf(t2) = SymTab.ClUChar))
 2883                 OR ((SymTab.ClassOf(t) = SymTab.ClUChar)
 2884                   AND (SymTab.ClassOf(t2) = SymTab.ClUChar))) THEN
 2885               (* UString concatenation: a UCHAR operand becomes a
 2886                  1-codepoint UString; the result is a descriptor in the
 2887                  shim's concat buffer.  Work on copies so neither
 2888                  operand is clobbered. *)
 2889               IF SymTab.ClassOf(t) = SymTab.ClUStr THEN
 2890                 QbeGen.CopyOp(q, q2a)
 2891               ELSE
 2892                 QbeGen.UStrFrom(q, q2a)
 2893               END;
 2894               IF SymTab.ClassOf(t2) = SymTab.ClUStr THEN
 2895                 QbeGen.UStrCat(q2a, q2, qt)
 2896               ELSE
 2897                 QbeGen.UStrFrom(q2, q2b);
 2898                 QbeGen.UStrCat(q2a, q2b, qt)
 2899               END;
 2900               t := SymTab.NewUStr();
 2901               QbeGen.CopyOp(qt, q)
 2902             ELSIF (op = SymTab.OpAdd)
 2903               AND (SymTab.StrCompat(t, t2)
 2904                 OR (SymTab.IsStrType(t)
 2905                   AND (SymTab.ClassOf(t2) = SymTab.ClChar))
 2906                 OR ((SymTab.ClassOf(t) = SymTab.ClChar)
 2907                   AND SymTab.IsStrType(t2))) THEN
 2908               (* string concatenation; a CHAR operand becomes a
 2909                  1-character string literal.  When both operands are
 2910                  constants, fold to a single string literal so a
 2911                  constructor element stays compile-time. *)
 2912               QbeGen.StrFold(q, q2, SymTab.ClassOf(t), SymTab.ClassOf(t2),
 2913                 qt, fok);
 2914               IF NOT fok THEN
 2915                 IF SymTab.StrCompat(t, t2) THEN
 2916                   QbeGen.StrCat(q, q2, qt)
 2917                 ELSIF SymTab.IsStrType(t) THEN
 2918                   QbeGen.DeclCharStr(q2, qs);
 2919                   QbeGen.StrCat(q, qs, qt)
 2920                 ELSE
 2921                   QbeGen.DeclCharStr(q, qs);
 2922                   QbeGen.StrCat(qs, q2, qt)
 2923                 END
 2924               END;
 2925               t := SymTab.NewStr();
 2926               QbeGen.CopyOp(qt, q)
 2927             ELSIF (t # SymTab.InvalidType) AND (t2 # SymTab.InvalidType)
 2928   AND (SymTab.ClassOf(t) = SymTab.ClSet)
 2929   AND (SymTab.ClassOf(t2) = SymTab.ClSet) THEN
 2930               lw := SymTab.SetWords(t); rw := SymTab.SetWords(t2);
 2931               mw := lw;
 2932               IF rw > mw THEN mw := rw END;
 2933               IF op = SymTab.OpAdd THEN
 2934                 QbeGen.SetBinOp(0, q, q2, lw, rw, qt)
 2935               ELSE
 2936                 QbeGen.SetBinOp(2, q, q2, lw, rw, qt)
 2937               END;
 2938               t := SymTab.NewSet(
 2939                      SymTab.NewSubR(0,
 2940                        VAL(INTEGER, mw) * 32 - 1));
 2941               QbeGen.CopyOp(qt, q)
 2942             ELSE
 2943               IF SymTab.ArithCheck(t, t2, FALSE, res2) THEN
 2944                 lt := t; rt := t2; t := res2
 2945               ELSE SemError(211); t := SymTab.InvalidType END;
 2946               IF t # SymTab.InvalidType THEN
 2947                 isL := SymTab.IsLongFamily(t);
 2948                 isR := SymTab.ClassOf(t) = SymTab.ClReal;
 2949                 folded := FALSE;
 2950                 IF (NOT isL) AND (NOT isR)
 2951    AND QbeGen.IsImm(q) AND QbeGen.IsImm(q2) THEN
 2952                   IF op = SymTab.OpAdd THEN
 2953                     folded := QbeGen.Fold2(0, q, q2, qf)
 2954                   ELSE
 2955                     folded := QbeGen.Fold2(1, q, q2, qf)
 2956                   END
 2957                 END;
 2958                 IF folded THEN QbeGen.CopyOp(qf, q)
 2959                 ELSE
 2960                 IF isL THEN
 2961                   IF SymTab.IsIntFamily(lt) THEN
 2962                     QbeGen.WidenLong(q, wq); QbeGen.CopyOp(wq, q)
 2963                   END;
 2964                   IF SymTab.IsIntFamily(rt) THEN
 2965                     QbeGen.WidenLong(q2, wq); QbeGen.CopyOp(wq, q2)
 2966                   END;
 2967                   QbeGen.NewTemp(qt);
 2968                   IF op = SymTab.OpAdd THEN
 2969                     QbeGen.Op3L("add", qt, q, q2)
 2970                   ELSE
 2971                     QbeGen.Op3L("sub", qt, q, q2)
 2972                   END
 2973                 ELSE
 2974                   QbeGen.NewTemp(qt);
 2975                   IF op = SymTab.OpAdd THEN
 2976                     QbeGen.Op3("add", qt, q, q2, isR)
 2977                   ELSE
 2978                     QbeGen.Op3("sub", qt, q, q2, isR)
 2979                   END
 2980                 END;
 2981                 QbeGen.CopyOp(qt, q)
 2982                 END
 2983               ELSE QbeGen.CopyOp("0", q)
 2984               END
 2985             END; .) } .
 2986    AddOp<VAR op: INTEGER>
 2987      = "+"                               (. op := SymTab.OpAdd; .)
 2988      | "-"                               (. op := SymTab.OpSub; .)
 2989      | "OR"                              (. op := SymTab.OpOr; .) .
 2990    Term<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal>
 2991                                          (. VAR t2, res2, lt, rt:
 2992                                                 SymTab.TypeIndex;
 2993                                               op: INTEGER;
 2994                                               q2, qt, wq, qf:
 2995                                                 QbeGen.QVal;
 2996                                               isR, isL, folded: BOOLEAN;
 2997                                               lw, rw, mw: CARDINAL;
 2998                                               lNext, lFalse, lDone, qr, qs: QbeGen.QVal;
 2999                                                astA, astB: AST.Node;
 3000                                                astOp: INTEGER; .)
 3001      = Fact<t, q> (. astA := astCur; .) { MulOp<op>            (. IF op = SymTab.OpAnd THEN
 3002                                               QbeGen.DelayBegin END; .)
 3003          Fact<t2, q2> (. astB := astCur; IF op = SymTab.OpAnd THEN
 3004                                                QbeGen.DelayEnd END; .)
 3005        (. astOp := AST.OpMul;
 3006           IF op = SymTab.OpSlash THEN astOp := AST.OpDiv
 3007           ELSIF op = SymTab.OpDiv THEN astOp := AST.OpDiv
 3008           ELSIF op = SymTab.OpMod THEN astOp := AST.OpMod
 3009           ELSIF op = SymTab.OpAnd THEN astOp := AST.OpAnd END;
 3010           astA := AST.MakeBin(AST.NkBinExpr, astOp, astA, astB);
 3011           astCur := astA;
 3012           IF op = SymTab.OpAnd THEN
 3013             (* short-circuit: if q is false the RHS is skipped *)
 3014             IF SymTab.BoolCheck(t) AND SymTab.BoolCheck(t2) THEN
 3015               t := SymTab.BoolType()
 3016             ELSE SemError(212); t := SymTab.InvalidType END;
 3017             IF t # SymTab.InvalidType THEN
 3018               QbeGen.Slot4(qs);
 3019               QbeGen.NewLabel(lNext);
 3020               QbeGen.NewLabel(lFalse);
 3021               QbeGen.NewLabel(lDone);
 3022               QbeGen.Jnz(q, lNext, lFalse);
 3023               QbeGen.EmitLabel(lNext);
 3024               QbeGen.DelayFlush;
 3025               QbeGen.StoreW(qs, q2);
 3026               QbeGen.Jmp(lDone);
 3027               QbeGen.EmitLabel(lFalse);
 3028               QbeGen.StoreW(qs, "0");
 3029               QbeGen.Jmp(lDone);
 3030               QbeGen.EmitLabel(lDone);
 3031               QbeGen.LoadW(qs, qr);
 3032               QbeGen.CopyOp(qr, q)
 3033             ELSE QbeGen.DelayFlush; QbeGen.CopyOp("0", q)
 3034             END
 3035           ELSIF (t # SymTab.InvalidType) AND (t2 # SymTab.InvalidType)
 3036   AND (SymTab.ClassOf(t) = SymTab.ClSet)
 3037   AND (SymTab.ClassOf(t2) = SymTab.ClSet) THEN
 3038             lw := SymTab.SetWords(t); rw := SymTab.SetWords(t2);
 3039             mw := lw;
 3040             IF rw > mw THEN mw := rw END;
 3041             IF op = SymTab.OpTimes THEN
 3042               QbeGen.SetBinOp(1, q, q2, lw, rw, qt)
 3043             ELSE
 3044               QbeGen.SetBinOp(3, q, q2, lw, rw, qt)
 3045             END;
 3046             t := SymTab.NewSet(
 3047                    SymTab.NewSubR(0,
 3048                      VAL(INTEGER, mw) * 32 - 1));
 3049             QbeGen.CopyOp(qt, q)
 3050           ELSE
 3051             IF SymTab.ArithCheck(t, t2,
 3052                  (op = SymTab.OpDiv) OR (op = SymTab.OpMod),
 3053                  res2) THEN
 3054               lt := t; rt := t2; t := res2
 3055             ELSE SemError(211); t := SymTab.InvalidType END;
 3056             IF t # SymTab.InvalidType THEN
 3057               isL := SymTab.IsLongFamily(t);
 3058               isR := SymTab.ClassOf(t) = SymTab.ClReal;
 3059               folded := FALSE;
 3060               IF (NOT isL) AND (NOT isR)
 3061    AND QbeGen.IsImm(q) AND QbeGen.IsImm(q2) THEN
 3062                 IF op = SymTab.OpTimes THEN
 3063                   folded := QbeGen.Fold2(2, q, q2, qf)
 3064                 ELSIF op = SymTab.OpDiv THEN
 3065                   folded := QbeGen.Fold2(3, q, q2, qf)
 3066                 ELSIF op = SymTab.OpMod THEN
 3067                   folded := QbeGen.Fold2(4, q, q2, qf)
 3068                 END
 3069               END;
 3070               IF folded THEN QbeGen.CopyOp(qf, q)
 3071               ELSE
 3072               IF isL THEN
 3073                 IF SymTab.IsIntFamily(lt) THEN
 3074                   QbeGen.WidenLong(q, wq); QbeGen.CopyOp(wq, q)
 3075                 END;
 3076                 IF SymTab.IsIntFamily(rt) THEN
 3077                   QbeGen.WidenLong(q2, wq); QbeGen.CopyOp(wq, q2)
 3078                 END;
 3079                 QbeGen.NewTemp(qt);
 3080                 IF op = SymTab.OpTimes THEN
 3081                   QbeGen.Op3L("mul", qt, q, q2)
 3082                 ELSIF (op = SymTab.OpDiv)
 3083                    OR (op = SymTab.OpSlash) THEN
 3084                   QbeGen.Op3L("div", qt, q, q2)
 3085                 ELSE
 3086                   QbeGen.Op3L("rem", qt, q, q2)
 3087                 END
 3088               ELSE
 3089                 QbeGen.NewTemp(qt);
 3090                 IF op = SymTab.OpTimes THEN
 3091                   QbeGen.Op3("mul", qt, q, q2, isR)
 3092                 ELSIF (op = SymTab.OpDiv)
 3093                    OR (op = SymTab.OpSlash) THEN
 3094                   QbeGen.Op3("div", qt, q, q2, isR)
 3095                 ELSE
 3096                   QbeGen.Op3("rem", qt, q, q2, isR)
 3097                 END
 3098               END;
 3099               QbeGen.CopyOp(qt, q)
 3100               END
 3101             ELSE QbeGen.CopyOp("0", q)
 3102             END
 3103           END; .) } .
 3104    MulOp<VAR op: INTEGER>
 3105      = "*"                               (. op := SymTab.OpTimes; .)
 3106      | "/"                               (. op := SymTab.OpSlash; .)
 3107      | "DIV"                             (. op := SymTab.OpDiv; .)
 3108      | "MOD"                             (. op := SymTab.OpMod; .)
 3109      | ( "AND" | "&" )                   (. op := SymTab.OpAnd; .) .
 3110    Fact<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal>
 3111                                          (. VAR s: ARRAY [0 .. 255] OF CHAR;
 3112                                               et, dt, t2, st, ct2, et2:
 3113                                                 SymTab.TypeIndex;
 3114                                               dk: INTEGER;
 3115                                               qd, q2, sq, qa, qm0, qr, qt:
 3116                                                 QbeGen.QVal;
 3117                                               qn, vn: SymTab.Name;
 3118                                               vt: SymTab.TypeIndex;
 3119                                               c1, c2: INTEGER;
 3120                                               lo, hi: INTEGER;
 3121                                               isMax: BOOLEAN;
 3122                                               called, isHigh, sfx, isCh,
 3123                                               isU, uok, isStr: BOOLEAN;
 3124                                               ucp: INTEGER; astIsLit: BOOLEAN;
 3125                                                astD: AST.Node;
 3126                                                astCall: BOOLEAN;
 3127                                                astNode, astNot: AST.Node;
 3128                                                j: CARDINAL;
 3129                                                astArg2: AST.Node;
 3130                                                astBrace: AST.Node;
 3131                                                astRes: AST.Node; .)
 3132      = (. astIsLit := FALSE; .)
 3133      ( integer                           (. LexString(s);
 3134                                             QbeGen.NormInt(s, q); IF twoPhase THEN astIsLit := TRUE; astCur := AST.MakeLeaf(AST.NkIntLit, s) END;
 3135                                             t := SymTab.IntType(); .)
 3136      | charConst                         (. LexString(s);
 3137                                             QbeGen.NormLit(s, q, isCh);
 3138                                             IF twoPhase THEN
 3139                                               astIsLit := TRUE;
 3140                                               astCur := AST.MakeLeaf(
 3141                                                 AST.NkCharLit, s)
 3142                                             END;
 3143                                             t := SymTab.CharType(); .)
 3144      | real                              (. LexString(s);
 3145                                             QbeGen.NormReal(s, q);
 3146                                             IF twoPhase THEN
 3147                                               astIsLit := TRUE;
 3148                                               astCur := AST.MakeLeaf(
 3149                                                 AST.NkRealLit, s)
 3150                                             END;
 3151                                             t := SymTab.RealType(); .)
 3152      | string                            (. LexString(s);
 3153                                             IF twoPhase THEN
 3154                                               astIsLit := TRUE;
 3155                                               astCur := AST.MakeLeaf(
 3156                                                 AST.NkStrLit, s)
 3157                                             END;
 3158                                             IF SymTab.StrLen(s) = 3 THEN
 3159                                               t := SymTab.CharType();
 3160                                               QbeGen.IntStr(
 3161                                                 QbeGen.CharVal(s), q)
 3162                                             ELSE t := SymTab.NewStr();
 3163                                               QbeGen.DeclStr(s, q);
 3164                                               (* a literal's value IS its
 3165                                                  static descriptor address *)
 3166                                               QbeGen.NoteAddr(q, q)
 3167                                             END; .)
 3168      | ustring                           (. LexString(s);
 3169                                             IF twoPhase THEN
 3170                                               astIsLit := TRUE;
 3171                                               astCur := AST.MakeLeaf(
 3172                                                 AST.NkStrLit, s)
 3173                                             END;
 3174                                             QbeGen.DeclUStr(s, q, isU, ucp,
 3175                                               uok);
 3176                                             IF NOT uok THEN
 3177                                               SemError(234);
 3178                                               t := SymTab.InvalidType
 3179                                             ELSIF isU THEN
 3180                                               t := SymTab.UCharType();
 3181                                               QbeGen.IntStr(ucp, q)
 3182                                             ELSE
 3183                                               t := SymTab.NewUStr();
 3184                                               QbeGen.NoteAddr(q, q)
 3185                                             END; .)
 3186      | Design<dt, dk, qd, qn, sfx>       (. astD := astCur; astCall := FALSE; astBrace := AST.NoNode;
 3187                                             astNArgs := 0; called := FALSE;
 3188                                             t := dt;
 3189                                             IF sfx THEN
 3190                                               IF dt =
 3191                                                  SymTab.InvalidType THEN
 3192                                                 QbeGen.CopyOp("0", q)
 3193                                               ELSIF (SymTab.ClassOf(dt) =
 3194                                                      SymTab.ClRecord)
 3195                                                  OR (SymTab.ClassOf(dt) =
 3196                                                      SymTab.ClSet)
 3197                                                  OR (SymTab.ClassOf(dt) =
 3198                                                      SymTab.ClArray)
 3199                                                  OR (SymTab.ClassOf(dt) =
 3200                                                      SymTab.ClClass) THEN
 3201                                                 QbeGen.CopyOp(qd, q)
 3202                                               ELSE QbeGen.ElemLoad(qd, dt,
 3203                                                 q)
 3204                                               END
 3205                                             ELSE QbeGen.CopyOp(qd, q)
 3206                                             END;
 3207                                             IF (dk = SymTab.KindVar)
 3208                                                OR (dk = SymTab.KindParam)
 3209                                                OR (dk =
 3210                                                   SymTab.KindField) THEN
 3211                                               IF sfx THEN
 3212                                                 QbeGen.NoteAddr(q, qd)
 3213                                               ELSE
 3214                                                 QbeGen.AddrOf(qn, qa);
 3215                                                 QbeGen.NoteAddr(q, qa)
 3216                                               END
 3217                                             ELSIF sfx
 3218   AND (dt #
 3219                                                   SymTab.InvalidType)
 3220   AND ((SymTab.ClassOf(dt) =
 3221                                                    SymTab.ClArray)
 3222                                                   OR (SymTab.ClassOf(dt) =
 3223                                                       SymTab.ClSet)
 3224                                                   OR (SymTab.ClassOf(dt) =
 3225                                                       SymTab.ClRecord)) THEN
 3226                                               QbeGen.NoteAddr(qd, qd)
 3227                                             END; .)
 3228        [ TypedBraceLit<dt, q>            (. t := dt; astCall := TRUE;
 3229                                               astBrace := astCur; .) ]
 3230        [ ArgList<qn, dt, qd, TRUE, FALSE, methCls, ct2, q2, called>
 3231                                          (. astCall := TRUE;
 3232                                             astNode := AstCallNode(astD);
 3233                                             astRes := astNode;
 3234                                             t := ct2;
 3235                                             QbeGen.CopyOp(q2, q);
 3236                                             sfx := FALSE; .)
 3237          { ResultComp<t, q, sfx, astRes> }
 3238                                          (. IF sfx THEN
 3239                                               IF t = SymTab.InvalidType THEN
 3240                                                 QbeGen.CopyOp("0", q)
 3241                                               ELSIF (SymTab.ClassOf(t) #
 3242                                                      SymTab.ClRecord)
 3243    AND (SymTab.ClassOf(t) # SymTab.ClSet)
 3244    AND (SymTab.ClassOf(t) # SymTab.ClArray)
 3245    AND (SymTab.ClassOf(t) # SymTab.ClClass) THEN
 3246                                                 QbeGen.ElemLoad(q, t, q2);
 3247                                                 QbeGen.CopyOp(q2, q)
 3248                                               END
 3249                                             END; .) ]
 3250                                          (. IF called THEN
 3251                                               astCur := astRes
 3252                                             ELSIF astCall THEN
 3253                                               astCur := astBrace
 3254                                             ELSE astCur := astD
 3255                                             END;
 3256                                              astIsLit := TRUE;
 3257                                              IF NOT called
 3258   AND (dk = SymTab.KindProc) THEN
 3259                                               (* bare zero-arg function
 3260                                                  call (parentheses may be
 3261                                                  omitted); a proper or
 3262                                                  parameterised proc here
 3263                                                  is 230 *)
 3264                                               IF (SymTab.ProcNPar(qn) = 0)
 3265   AND (SymTab.ProcRes(qn) #
 3266                                                     SymTab.InvalidType) THEN
 3267                                                 QbeGen.Mangled(qn,
 3268                                                   SymTab.ProcUid(qn), qm0);
 3269                                                 QbeGen.CallBegin(qm0,
 3270                                                   SymTab.ProcRes(qn),
 3271                                                   SymTab.ProcDepthOf(qn),
 3272                                                   SymTab.IsExternal(qn));
 3273                                                 QbeGen.CallEnd(TRUE, q);
 3274                                                 t := SymTab.ProcRes(qn)
 3275                                               ELSE
 3276                                                 (* procedure used as a
 3277                                                    value (assign to a
 3278                                                    procedure variable):
 3279                                                    its code address *)
 3280                                                 t := SymTab.ProcTypeOf(qn);
 3281                                                 QbeGen.Mangled(qn,
 3282                                                   SymTab.ProcUid(qn), qm0);
 3283                                                 QbeGen.ProcAddr(qm0, q)
 3284                                               END
 3285                                             END; .)
 3286      | ( "HIGH"                          (. isHigh := TRUE; .)
 3287        | ( "LEN" | "LENGTH" )            (. isHigh := FALSE; .) )
 3288        "(" ( Design<dt, dk, qd, qn, sfx> (. isStr := FALSE;
 3289                                              isU := FALSE; .)
 3290            | string                       (. LexString(s); astCur := AST.MakeLeaf(AST.NkStrLit, s);
 3291                                              isStr := TRUE;
 3292                                              isU := FALSE;
 3293                                              IF SymTab.StrLen(s) = 3 THEN
 3294                                                dt := SymTab.CharType();
 3295                                                QbeGen.IntStr(QbeGen.CharVal(s),
 3296                                                  qd)
 3297                                              ELSE
 3298                                                dt := SymTab.NewStr();
 3299                                                QbeGen.DeclStr(s, qd);
 3300                                                QbeGen.NoteAddr(qd, qd)
 3301                                              END;
 3302                                              dk := -1;
 3303                                              qn[0] := CHR(0); .)
 3304            | ustring                      (. LexString(s); astCur := AST.MakeLeaf(AST.NkStrLit, s);
 3305                                              QbeGen.DeclUStr(s, qd, isU, ucp,
 3306                                                uok);
 3307                                              isStr := FALSE;
 3308                                              IF NOT uok THEN
 3309                                                SemError(234);
 3310                                                dt := SymTab.InvalidType
 3311                                              ELSIF isU THEN
 3312                                                (* one codepoint: a UCHAR;
 3313                                                   LEN is 1, HIGH is 0 *)
 3314                                                dt := SymTab.UCharType();
 3315                                                QbeGen.IntStr(ucp, qd)
 3316                                              ELSE
 3317                                                dt := SymTab.NewUStr();
 3318                                                QbeGen.NoteAddr(qd, qd)
 3319                                              END;
 3320                                              dk := -1;
 3321                                              qn[0] := CHR(0); .) )
 3322        ")"
 3323                                          (. astNode := AST.MakeNode(AST.NkCall);
 3324     IF isHigh THEN AST.SetChild(astNode, 0,
 3325       AST.MakeLeaf(AST.NkIdent, "HIGH"))
 3326     ELSE AST.SetChild(astNode, 0,
 3327       AST.MakeLeaf(AST.NkIdent, "LEN")) END;
 3328     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3329     astCur := astNode; astIsLit := TRUE;
 3330                                             IF (dt # SymTab.InvalidType)
 3331    AND (SymTab.ClassOf(dt) = SymTab.ClUStr) THEN
 3332                                               (* UString: the count is
 3333                                                  the descriptor header *)
 3334                                               IF isHigh THEN
 3335                                                 QbeGen.UStrLen(qd, qr);
 3336                                                 QbeGen.DecQ(qr)
 3337                                               ELSE
 3338                                                 QbeGen.UStrLen(qd, qr)
 3339                                               END;
 3340                                               t := SymTab.IntType();
 3341                                               QbeGen.CopyOp(qr, q)
 3342                                             ELSIF (dt # SymTab.InvalidType)
 3343    AND (SymTab.ClassOf(dt) = SymTab.ClUChar) THEN
 3344                                               (* single UCHAR codepoint *)
 3345                                               IF isHigh THEN
 3346                                                 QbeGen.CopyOp("0", qr)
 3347                                               ELSE
 3348                                                 QbeGen.CopyOp("1", qr)
 3349                                               END;
 3350                                               t := SymTab.IntType();
 3351                                               QbeGen.CopyOp(qr, q)
 3352                                             ELSIF isStr THEN
 3353                                               (* fold: content length at
 3354                                                  compile time *)
 3355                                               IF SymTab.StrLen(s) = 3 THEN
 3356                                                 c1 := 1
 3357                                               ELSE
 3358                                                 c1 :=
 3359                                                   SymTab.StrLen(s) - 2
 3360                                               END;
 3361                                               IF isHigh THEN
 3362                                                 DEC(c1)
 3363                                               END;
 3364                                               QbeGen.IntStr(c1, qr);
 3365                                               t := SymTab.IntType();
 3366                                               QbeGen.CopyOp(qr, q)
 3367                                             ELSIF dt = SymTab.InvalidType THEN
 3368                                               t := SymTab.InvalidType;
 3369                                               QbeGen.CopyOp("0", q)
 3370                                             ELSIF SymTab.ClassOf(dt) #
 3371                                                   SymTab.ClArray THEN
 3372                                               SemError(217);
 3373                                               t := SymTab.InvalidType;
 3374                                               QbeGen.CopyOp("0", q)
 3375                                             ELSE
 3376                                               IF isHigh THEN
 3377                                                 IF SymTab.IsOpenArray(dt) THEN
 3378                                                   QbeGen.OpenHi(qd, qr)
 3379                                                 ELSE
 3380                                                   QbeGen.IntStr(
 3381                                                     SymTab.ArrayHi(dt), qr)
 3382                                                 END
 3383                                               ELSE
 3384                                                 IF SymTab.IsOpenArray(dt) THEN
 3385                                                   QbeGen.LoadCount(qd, qr)
 3386                                                 ELSE
 3387                                                   QbeGen.IntStr(VAL(
 3388                                                     INTEGER,
 3389                                                     SymTab.ArrayLen(dt)),
 3390                                                     qr)
 3391                                                 END
 3392                                               END;
 3393                                                t := SymTab.IntType();
 3394                                                QbeGen.CopyOp(qr, q)
 3395                                              END; .)
 3396      | ( "SIZE" | "TSIZE" ) "(" Design<dt, dk, qd, qn, sfx> ")"
 3397      (. astNode := AST.MakeNode(AST.NkCall);
 3398     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "SIZE"));
 3399     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3400     astCur := astNode; astIsLit := TRUE; .)
 3401                                          (. IF dt = SymTab.InvalidType THEN
 3402                                               t := SymTab.InvalidType;
 3403                                               QbeGen.CopyOp("0", q)
 3404                                             ELSE
 3405                                               QbeGen.IntStr(VAL(INTEGER,
 3406                                                 SymTab.ObjectSize(dt)), q);
 3407                                               t := SymTab.IntType()
 3408                                             END; .)
 3409      | ( "SHIFT"                         (. isMax := FALSE; .)
 3410        | "ROTATE"                        (. isMax := TRUE; .) )
 3411        "(" Expr<et, q> (. astArg2 := astCur; .) "," Expr<et2, q2> ")"
 3412                                          (. astNode := AST.MakeNode(AST.NkCall);
 3413     IF isMax THEN AST.SetChild(astNode, 0,
 3414       AST.MakeLeaf(AST.NkIdent, "ROTATE"))
 3415     ELSE AST.SetChild(astNode, 0,
 3416       AST.MakeLeaf(AST.NkIdent, "SHIFT")) END;
 3417     IF astArg2 # AST.NoNode THEN AST.SetChild(astNode, 1, astArg2) END;
 3418     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 2, astCur) END;
 3419     astCur := astNode; astIsLit := TRUE;
 3420                                             (* set shift/rotate: isMax
 3421                                                doubles as "rotate" *)
 3422                                             IF (et # SymTab.InvalidType)
 3423                                                AND (SymTab.ClassOf(et) =
 3424                                                   SymTab.ClSet) THEN
 3425                                               QbeGen.SetShift(q, q2,
 3426                                                 SymTab.SetWords(et),
 3427                                                 SymTab.SetCount(et), isMax,
 3428                                                 qt);
 3429                                               t := et;
 3430                                               QbeGen.CopyOp(qt, q)
 3431                                             ELSE SemError(230);
 3432                                               t := SymTab.InvalidType;
 3433                                               QbeGen.CopyOp("0", q)
 3434                                             END; .)
 3435      | ( "MIN"                           (. isMax := FALSE; .)
 3436        | "MAX"                           (. isMax := TRUE; .) )
 3437        "(" Design<dt, dk, qd, qn, sfx> ")"
 3438                                          (. astNode := AST.MakeNode(AST.NkCall);
 3439     IF isMax THEN AST.SetChild(astNode, 0,
 3440       AST.MakeLeaf(AST.NkIdent, "MAX"))
 3441     ELSE AST.SetChild(astNode, 0,
 3442       AST.MakeLeaf(AST.NkIdent, "MIN")) END;
 3443     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3444     astCur := astNode; astIsLit := TRUE;
 3445                                             IF (dt # SymTab.InvalidType)
 3446   AND (SymTab.ClassOf(dt) = SymTab.ClReal) THEN
 3447                                               (* REAL/LONGREAL: the
 3448                                                  implementation bounds *)
 3449                                               IF isMax THEN
 3450                                                 QbeGen.NormReal(
 3451                                                   "3.402823e38", q)
 3452                                               ELSE QbeGen.NormReal(
 3453                                                   "-3.402823e38", q)
 3454                                               END;
 3455                                               t := SymTab.RealType()
 3456                                             ELSIF (dt #
 3457                                                SymTab.InvalidType)
 3458   AND (SymTab.ClassOf(dt) =
 3459                                                   SymTab.ClLong) THEN
 3460                                               IF isMax THEN
 3461                                                 QbeGen.CopyOp(
 3462                                                   "9223372036854775807", q)
 3463                                               ELSE QbeGen.CopyOp(
 3464                                                   "-9223372036854775808", q)
 3465                                               END;
 3466                                               t := SymTab.LongType()
 3467                                             ELSIF SymTab.TypeBounds(dt, lo,
 3468                                                      hi) THEN
 3469                                               IF isMax THEN
 3470                                                 QbeGen.IntStr(hi, q)
 3471                                               ELSE QbeGen.IntStr(lo, q)
 3472                                               END;
 3473                                               t := SymTab.IntType()
 3474                                             ELSE SemError(230);
 3475                                               t := SymTab.InvalidType;
 3476                                               QbeGen.CopyOp("0", q)
 3477                                             END; .)
 3478      | "ADR" "(" Design<dt, dk, qd, qn, sfx> ")"
 3479      (. astNode := AST.MakeNode(AST.NkCall);
 3480     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "ADR"));
 3481     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3482     astCur := astNode; astIsLit := TRUE; .)
 3483                                          (. IF dt = SymTab.InvalidType THEN
 3484                                               t := SymTab.InvalidType;
 3485                                               QbeGen.CopyOp("0", q)
 3486                                             ELSE
 3487                                               IF sfx THEN
 3488                                                 QbeGen.CopyOp(qd, q)
 3489                                               ELSIF (dk = SymTab.KindVar)
 3490                                                  OR (dk = SymTab.KindParam) THEN
 3491                                                 QbeGen.AddrOf(qn, q)
 3492                                               ELSE SemError(230);
 3493                                                 QbeGen.CopyOp("0", q)
 3494                                               END;
 3495                                               t := SymTab.AddrType()
 3496                                             END; .)
 3497      | "CHR" "(" Expr<et, q> ")"
 3498      (. astNode := AST.MakeNode(AST.NkCall);
 3499     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "CHR"));
 3500     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3501     astCur := astNode; astIsLit := TRUE; .)
 3502                                          (. IF (et # SymTab.InvalidType)
 3503   AND NOT SymTab.IsIntFamily(et) THEN
 3504                                               SemError(211) END;
 3505                                             t := SymTab.CharType(); .)
 3506      | ( "ORD" | "ORDL" ) "(" Expr<et, q> ")"
 3507      (. astNode := AST.MakeNode(AST.NkCall);
 3508     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "ORD"));
 3509     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3510     astCur := astNode; astIsLit := TRUE; .)
 3511                                          (. IF et # SymTab.InvalidType THEN
 3512                                               IF (SymTab.ClassOf(et) #
 3513                                                   SymTab.ClChar)
 3514   AND (SymTab.ClassOf(et) #
 3515                                                     SymTab.ClBool)
 3516   AND (SymTab.ClassOf(et) #
 3517                                                     SymTab.ClEnum)
 3518   AND NOT SymTab.IsIntFamily(et) THEN
 3519                                                 SemError(211) END
 3520                                             END;
 3521                                             t := SymTab.IntType(); .)
 3522      | "CAP" "(" Expr<et, q> ")"
 3523      (. astNode := AST.MakeNode(AST.NkCall);
 3524     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "CAP"));
 3525     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3526     astCur := astNode; astIsLit := TRUE; .)
 3527                                          (. QbeGen.CapQ(q, qa);
 3528                                             QbeGen.CopyOp(qa, q);
 3529                                             t := SymTab.CharType(); .)
 3530      | "UCHR" "(" Expr<et, q> ")"
 3531      (. astNode := AST.MakeNode(AST.NkCall);
 3532     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "UCHR"));
 3533     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3534     astCur := astNode; astIsLit := TRUE; .)
 3535                                          (. (* UCHR: the UCHAR constructor.
 3536                                                CHAR -> UCHAR (identity);
 3537                                                INTEGER familly -> UCHAR
 3538                                                (codepoint value). *)
 3539                                             IF (et # SymTab.InvalidType)
 3540    AND (SymTab.ClassOf(et) # SymTab.ClChar)
 3541    AND NOT SymTab.IsIntFamily(et) THEN
 3542                                               SemError(211) END;
 3543                                             t := SymTab.UCharType(); .)
 3544      | "CHR8" "(" Expr<et, q> ")"
 3545      (. astNode := AST.MakeNode(AST.NkCall);
 3546     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "CHR8"));
 3547     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3548     astCur := astNode; astIsLit := TRUE; .)
 3549                                          (. IF (et # SymTab.InvalidType)
 3550    AND (SymTab.ClassOf(et) # SymTab.ClUChar) THEN
 3551                                               SemError(211) END;
 3552                                             QbeGen.WidenLong(q, qa);
 3553                                             QbeGen.CheckRange(qa, "0", "255");
 3554                                             t := SymTab.CharType(); .)
 3555      | "UORD" "(" Expr<et, q> ")"
 3556      (. astNode := AST.MakeNode(AST.NkCall);
 3557     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "UORD"));
 3558     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3559     astCur := astNode; astIsLit := TRUE; .)
 3560                                          (. (* UORD(u): the codepoint as a
 3561                                                32-bit ordinal (INTEGER),
 3562                                                cf. ORD for CHAR. *)
 3563                                             IF (et # SymTab.InvalidType)
 3564    AND (SymTab.ClassOf(et) # SymTab.ClUChar) THEN
 3565                                               SemError(211) END;
 3566                                             t := SymTab.IntType(); .)
 3567      | "ABS" "(" Expr<et, q> ")"
 3568      (. astNode := AST.MakeNode(AST.NkCall);
 3569     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "ABS"));
 3570     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 1, astCur) END;
 3571     astCur := astNode; astIsLit := TRUE; .)
 3572                                          (. IF (et # SymTab.InvalidType)
 3573   AND NOT SymTab.IsIntFamily(et)
 3574   AND (SymTab.ClassOf(et) #
 3575                                                  SymTab.ClReal) THEN
 3576                                               SemError(211)
 3577                                             ELSE QbeGen.AbsQ(q, qa,
 3578                                                    SymTab.ClassOf(et) =
 3579                                                      SymTab.ClReal);
 3580                                               QbeGen.CopyOp(qa, q)
 3581                                             END;
 3582                                             t := et; .)
 3583      | "VAL" "(" GetIdent<vn> (. astArg2 := AST.MakeLeaf(AST.NkIdent, vn); .) "," Expr<et, q> ")"
 3584      (. astNode := AST.MakeNode(AST.NkCall);
 3585     AST.SetChild(astNode, 0, AST.MakeLeaf(AST.NkIdent, "VAL"));
 3586     IF astArg2 # AST.NoNode THEN AST.SetChild(astNode, 1, astArg2) END;
 3587     IF astCur # AST.NoNode THEN AST.SetChild(astNode, 2, astCur) END;
 3588     astCur := astNode; astIsLit := TRUE; .)
 3589                                          (. IF NOT SymTab.Lookup(vn) THEN
 3590                                               SemError(201);
 3591                                               t := SymTab.InvalidType
 3592                                             ELSE vt := SymTab.SymType(vn);
 3593                                               IF vt = SymTab.InvalidType THEN
 3594                                                 t := SymTab.InvalidType
 3595                                               ELSIF et =
 3596                                                  SymTab.InvalidType THEN
 3597                                                 t := vt
 3598                                               ELSE
 3599                                                 c1 := SymTab.ClassOf(et);
 3600                                                 c2 := SymTab.ClassOf(vt);
 3601                                                 IF (c1 = SymTab.ClInt)
 3602    AND (c2 = SymTab.ClLong) THEN
 3603                                                   QbeGen.WidenLong(q, qa);
 3604                                                   QbeGen.CopyOp(qa, q);
 3605                                                   t := vt
 3606                                                 ELSIF (c1 = SymTab.ClLong)
 3607    AND (c2 = SymTab.ClInt) THEN
 3608                                                   QbeGen.NarrowLong(q, qa);
 3609                                                   QbeGen.CopyOp(qa, q);
 3610                                                   t := vt
 3611                                                 ELSIF (c1 = SymTab.ClInt)
 3612    AND (c2 = SymTab.ClReal) THEN
 3613                                                   QbeGen.ConvIR(q, qa);
 3614                                                   QbeGen.CopyOp(qa, q);
 3615                                                   t := vt
 3616                                                 ELSIF (c1 = SymTab.ClLong)
 3617    AND (c2 = SymTab.ClReal) THEN
 3618                                                   QbeGen.ConvLR(q, qa);
 3619                                                   QbeGen.CopyOp(qa, q);
 3620                                                   t := vt
 3621                                                 ELSIF (c1 = SymTab.ClReal)
 3622    AND (c2 = SymTab.ClInt) THEN
 3623                                                   QbeGen.ConvRI(q, qa);
 3624                                                   QbeGen.CopyOp(qa, q);
 3625                                                   t := vt
 3626                                                 ELSIF (c1 = SymTab.ClReal)
 3627    AND (c2 = SymTab.ClLong) THEN
 3628                                                   QbeGen.ConvRL(q, qa);
 3629                                                   QbeGen.CopyOp(qa, q);
 3630                                                   t := vt
 3631                                                 ELSIF ((c1 = SymTab.ClInt)
 3632                                                     OR (c1 =
 3633                                                        SymTab.ClChar)
 3634                                                     OR (c1 =
 3635                                                        SymTab.ClBool)
 3636                                                     OR (c1 =
 3637                                                        SymTab.ClEnum))
 3638   AND ((c2 = SymTab.ClInt)
 3639                                                     OR (c2 =
 3640                                                        SymTab.ClChar)
 3641                                                     OR (c2 =
 3642                                                        SymTab.ClBool)
 3643                                                     OR (c2 =
 3644                                                        SymTab.ClEnum)) THEN
 3645                                                   t := vt
 3646                                                 ELSIF (c1 = SymTab.ClPtr)
 3647   AND (c2 = SymTab.ClPtr) THEN
 3648                                                   t := vt
 3649                                                 ELSIF (c1 = SymTab.ClReal)
 3650   AND (c2 = SymTab.ClReal) THEN
 3651                                                   t := vt
 3652                                                 ELSE SemError(230);
 3653                                                   t := SymTab.InvalidType
 3654                                                 END
 3655                                               END
 3656                                             END; .)
 3657      | "(" Expr<et, q> ")"               (. t := et; astIsLit := TRUE; .)
 3658      | SetLit<st, sq>                    (. astIsLit := TRUE; t := st;
 3659                                             QbeGen.CopyOp(sq, q); .)
 3660      | ( "NOT" | "~" ) Fact<t2, q2>      (. astNot := astCur;
 3661                                             IF SymTab.BoolCheck(t2) THEN
 3662                                               t := SymTab.BoolType()
 3663                                             ELSE SemError(212);
 3664                                               t := SymTab.InvalidType END;
 3665                                             IF t # SymTab.InvalidType THEN
 3666                                               QbeGen.NotQ(q2, q)
 3667                                             ELSE QbeGen.CopyOp("0", q)
 3668                                             END;
 3669                                             astIsLit := TRUE;
 3670                                             astCur := AST.MakeUn(
 3671                                               AST.NkUnary, AST.OpNot, astNot); .)
 3672      )
 3673      (. IF NOT astIsLit THEN astCur := AST.NoNode END; .) .
 3674    (* Set literals are SET OF [0..255] (8 words); elements validated
 3675       0..255 statically when foldable (222 otherwise), runtime trap
 3676       for computed elements. Ranges always lower via SetRange. *)
 3677    SetLit<VAR t: SymTab.TypeIndex; VAR q: QbeGen.QVal>
 3678                                          (. VAR astNode: AST.Node; .)
 3679      = "{"                               (. t := SymTab.NewSet(
 3680                                               SymTab.NewSubR(0, 255));
 3681                                             astNode := AST.MakeNode(AST.NkSetLit);
 3682                                             QbeGen.NewSetTemp(8, q);
 3683                                             QbeGen.SetZero(q, 8); .)
 3684        [ SetElem<t, q, astNode> { "," SetElem<t, q, astNode> } ]
 3685        "}"                               (. astCur := astNode; .) .
 3686    (* Typed brace constructor: TypeName{ elems } — BITSET{0} (a set)
 3687       or ArrayName{...} (an array constructor, GNU Modula-2).  The
 3688       declared type sets the width (set) or element type (array). *)
 3689    TypedBraceLit<vt: SymTab.TypeIndex; VAR q: QbeGen.QVal>
 3690                                          (. VAR nw: CARDINAL;
 3691                                               astNode, astTail: AST.Node;
 3692                                               savedCls: INTEGER; .)
 3693      = "{"                               (. savedCls := braceCls;
 3694                                             astNode := AST.MakeNode(AST.NkBraceLit);
 3695                                             AST.SetTy(astNode, vt);
 3696                                             astTail := astNode;
 3697                                             IF vt = SymTab.InvalidType THEN
 3698                                               braceCls := -1
 3699                                             ELSE braceCls :=
 3700                                                    SymTab.ClassOf(vt)
 3701                                             END;
 3702                                             IF braceCls = SymTab.ClSet THEN
 3703                                               IF vt = SymTab.InvalidType THEN
 3704                                                 nw := 8
 3705                                               ELSE nw := SymTab.SetWords(vt);
 3706                                                 IF nw = 0 THEN nw := 8 END
 3707                                               END;
 3708                                               QbeGen.NewSetTemp(nw, q);
 3709                                               QbeGen.SetZero(q, nw)
 3710                                             ELSIF (braceCls =
 3711                                                    SymTab.ClArray)
 3712                                                OR (braceCls =
 3713                                                    SymTab.ClRecord)
 3714                                                OR (braceCls =
 3715                                                    SymTab.ClClass) THEN
 3716                                               QbeGen.CtorBegin(vt)
 3717                                             ELSE
 3718                                               IF vt # SymTab.InvalidType THEN
 3719                                                 SemError(230) END;
 3720                                               braceCls := -1
 3721                                             END; .)
 3722        [ BraceElem<vt, q, astNode, astTail>
 3723          { "," BraceElem<vt, q, astNode, astTail> } ]
 3724        "}"                               (. IF (braceCls = SymTab.ClArray)
 3725                                                OR (braceCls =
 3726                                                   SymTab.ClRecord)
 3727                                                OR (braceCls =
 3728                                                   SymTab.ClClass) THEN
 3729                                               QbeGen.CtorEnd(q)
 3730                                             ELSIF braceCls # SymTab.ClSet THEN
 3731                                               QbeGen.CopyOp("0", q)
 3732                                             END;
 3733                                             braceCls := savedCls; .)
 3734                                          (. astCur := astNode; .) .
 3735    BraceElem<vt: SymTab.TypeIndex; VAR sq: QbeGen.QVal;
 3736              VAR node, tail: AST.Node>
 3737                                          (. VAR et, et2: SymTab.TypeIndex;
 3738                                               qe, q2: QbeGen.QVal;
 3739                                               v, v2, reps, k: INTEGER;
 3740                                               elem: SymTab.TypeIndex;
 3741                                               lo: INTEGER;
 3742                                               span: CARDINAL;
 3743                                               cl, cl2: INTEGER;
 3744                                               hasR, hasB: BOOLEAN;
 3745                                               astEl: AST.Node; .)
 3746      =                                   (. hasR := FALSE; hasB := FALSE; .)
 3747        Expr<et, qe> (. astEl := astCur; .)
 3748        [ ".." Expr<et2, q2>              (. astEl := AST.MakeBin(
 3749                                               AST.NkSubrange, 0, astEl, astCur);
 3750                                             hasR := TRUE; .) ]
 3751        [ "BY" Expr<et2, q2>              (. hasB := TRUE; .) ]
 3752                                          (. IF braceCls = SymTab.ClSet THEN
 3753                                               IF hasB THEN SemError(230) END;
 3754                                               lo := SymTab.SetBaseLo(vt);
 3755                                               span := SymTab.SetCount(vt);
 3756                                               IF (et = SymTab.InvalidType)
 3757                                                  OR (hasR AND (et2 =
 3758                                                     SymTab.InvalidType)) THEN
 3759                                               ELSE cl :=
 3760                                                      SymTab.ClassOf(et);
 3761                                                 IF hasR THEN
 3762                                                   cl2 :=
 3763                                                     SymTab.ClassOf(et2)
 3764                                                 ELSE cl2 := SymTab.ClInt
 3765                                                 END;
 3766                                                 IF NOT SymTab.SetElemClassOk(cl)
 3767                                                    OR (hasR AND NOT
 3768                                                       SymTab.SetElemClassOk(cl2))
 3769                                                 THEN
 3770                                                   SemError(222)
 3771                                                 ELSIF hasR
 3772   AND SymTab.ConstInt(qe, v)
 3773   AND SymTab.ConstInt(q2,
 3774                                                       v2)
 3775   AND ((v < lo)
 3776                                                       OR (v2 < lo)
 3777                                                       OR (v >= lo +
 3778                                                          VAL(INTEGER, span))
 3779                                                       OR (v2 >= lo +
 3780                                                          VAL(INTEGER, span))
 3781                                                       OR (v > v2)) THEN
 3782                                                   SemError(222)
 3783                                                  ELSIF hasR THEN
 3784                                                    QbeGen.SetRange(sq, qe, q2,
 3785                                                      lo, span)
 3786                                                  ELSIF SymTab.ConstInt(qe,
 3787                                                          v)
 3788   AND ((v < lo)
 3789                                                        OR (v >= lo +
 3790                                                           VAL(INTEGER,
 3791                                                             span))) THEN
 3792                                                    SemError(222)
 3793                                                  ELSE QbeGen.SetBit(sq, qe,
 3794                                                    lo, span)
 3795                                                 END
 3796                                               END
 3797                                             ELSIF (braceCls = SymTab.ClArray)
 3798                                                OR (braceCls =
 3799                                                   SymTab.ClRecord)
 3800                                                OR (braceCls =
 3801                                                   SymTab.ClClass) THEN
 3802                                               IF hasR THEN SemError(230) END;
 3803                                               reps := 1;
 3804                                               IF hasB THEN
 3805                                                 IF SymTab.ConstInt(q2, v2)
 3806   AND (v2 >= 1) THEN
 3807                                                   reps := v2
 3808                                                 ELSE SemError(230)
 3809                                                 END
 3810                                               END;
 3811                                               k := 0;
 3812                                               WHILE k < reps DO
 3813                                                 QbeGen.CtorElem(qe);
 3814                                                 INC(k)
 3815                                               END
 3816                                             END; .)
 3817                                          (. AstAppend(AST.NkBlock,
 3818                                               node, tail, astEl); .) .
 3819    SetElem<st: SymTab.TypeIndex; sq: QbeGen.QVal; node: AST.Node>         (. VAR et, et2: SymTab.TypeIndex;
 3820                                               qe, q2: QbeGen.QVal;
 3821                                               v, v2: INTEGER;
 3822                                               lo: INTEGER;
 3823                                               span: CARDINAL;
 3824                                               cl, cl2: INTEGER;
 3825                                               hasR: BOOLEAN;
 3826                                               astEl: AST.Node; .)
 3827      =                                   (. hasR := FALSE; .)
 3828        Expr<et, qe> (. astEl := astCur; .)
 3829        [ ".." Expr<et2, q2>              (. astEl := AST.MakeBin(
 3830                                               AST.NkSubrange, 0, astEl, astCur);
 3831                                             hasR := TRUE; .) ]
 3832                                          (. lo := SymTab.SetBaseLo(st);
 3833                                             span := SymTab.SetCount(st);
 3834                                             IF (et = SymTab.InvalidType)
 3835                                                OR (hasR AND (et2 =
 3836                                                   SymTab.InvalidType)) THEN
 3837                                             ELSE cl :=
 3838                                                    SymTab.ClassOf(et);
 3839                                               IF hasR THEN
 3840                                                 cl2 :=
 3841                                                   SymTab.ClassOf(et2)
 3842                                               ELSE cl2 := SymTab.ClInt
 3843                                               END;
 3844                                               IF NOT SymTab.SetElemClassOk(cl)
 3845                                                  OR (hasR AND NOT
 3846                                                     SymTab.SetElemClassOk(cl2))
 3847                                               THEN
 3848                                                 SemError(222)
 3849                                               ELSIF hasR
 3850   AND SymTab.ConstInt(qe, v)
 3851   AND SymTab.ConstInt(q2,
 3852                                                     v2)
 3853   AND ((v < lo)
 3854                                                     OR (v2 < lo)
 3855                                                     OR (v >= lo +
 3856                                                        VAL(INTEGER, span))
 3857                                                     OR (v2 >= lo +
 3858                                                        VAL(INTEGER, span))
 3859                                                     OR (v > v2)) THEN
 3860                                                 SemError(222)
 3861                                                ELSIF hasR THEN
 3862                                                  QbeGen.SetRange(sq, qe, q2,
 3863                                                    lo, span)
 3864                                                ELSIF SymTab.ConstInt(qe,
 3865                                                        v)
 3866   AND ((v < lo)
 3867                                                      OR (v >= lo +
 3868                                                         VAL(INTEGER,
 3869                                                           span))) THEN
 3870                                                  SemError(222)
 3871                                                ELSE QbeGen.SetBit(sq, qe,
 3872                                                  lo, span)
 3873                                               END
 3874                                             END; .)
 3875                                          (. AST.SetChild(node,
 3876                                               AST.NChild(node), astEl); .) .
 3877    GetIdent<VAR n: SymTab.Name>
 3878      = ident                             (. LexName(n); .) .
 3879  
 3880  END M2.

    0 errors


Statistics:

  nr of terminals:       104 (limit   400)
  nr of non-terminals:    85 (limit   210)
  nr of pragmas:           0 (limit   396)
  nr of symbolnodes:     189 (limit   500)
  nr of graphnodes:     1114 (limit  1500)
  nr of conditionsets:    11 (limit   100)
  nr of charactersets:    16 (limit   250)