M2compiler-V1/M2c.atg

COMPILER M2c
(* Modula-2 program modules with procedures and composites, MC64 backend
   (see MGen for details).

   - program module only, no DEFINITION / IMPLEMENTATION split
   - no local modules, no EXPORT, no PRIORITY
   - procedures: declarations (nested), value and VAR parameters,
     functions with RETURN, recursion, FORWARD headings;
     no procedure types/variables, no cones
   - composites (Phase 3): fixed ARRAYs (bounds, 1D/multi-D indexing,
     unchecked, byte-packed CHAR/BOOLEAN), RECORDs (field offsets,
     .field, WITH incl. nested), SETs (+ union, - difference,
     * intersection, inclusive .. ranges), POINTERs (NEW/DISPOSE via
     VM ALLOCATE, ^, NIL), strings (ARRAY OF CHAR literal assign).
     Open arrays deferred; whole array/record copy deferred except
     string literals; VAR actuals must be simple (no a[i]/p^/fields
     as VAR actuals, 233); value composite params rejected (230);
     composite function returns rejected (unchecked, avoid wrong LEAVE).
   - statements: assignment, procedure call, IF, CASE, WHILE,
     REPEAT, LOOP/EXIT, FOR, WITH, RETURN, NEW, DISPOSE
   - symbol table (SymTab) with static type checking: error codes
     200/201/202 and 210-224 (as before), plus 231 (procedure
     forward mismatch or missing body), 232 (bad RETURN), 233
     (invalid procedure call); same lenient rules (single pass,
     declare-before-use, except POINTER bases may be same-scope
     aliases with structural pointer compatibility in Assignable;
     INTEGER, CARDINAL and subranges form one
     integer family; no mixed INTEGER/REAL arithmetic; INTEGER
     assigns to REAL; 1-character literal is CHAR; InvalidType
     suppresses follow-on errors)
   - backend (MGen): single-module MC64 image <ModName>.MC4,
     runnable with mcint. Procedures take table entries 1..N
     (0 = module body), run with ENTER frames, called via ED
     (global), EC (directly nested) or EE (display walk); actuals
     evaluate left-to-right into temps, then push reversed.
     Lowered: scalar + composite globals/frame vars (multi-slot,
     byte sizes, field/element offsets), CONST literals,
     SET masks with literals/ranges/IN/=/#/+-/*; full scalar +
     composite expressions (scaled indexing via IdxScale, field
     via FieldAdd, deref via 41H/60H, byte ops 0DH/1DH for CHAR);
     control flow via E0/E1 jumps; composite assign via
     StoreIndir0/StoreByte (scalar elems) and copy_block (strings).
     The rest parses and type-checks
     but gets error 230: open arrays, whole array/record copy
     (except string literals), value composite params/returns,
     non-literal CONST expressions and BY steps,
     EXIT outside LOOP, imported names used as values.
   - test convention (the language has no I/O): a global
       VAR ExitCode : INTEGER;
     is printed as decimal + CRLF through an embedded helper;
     without it the program just ends.
   - known semantic edges: INTEGER DIV/MOD truncate toward zero;
     CARDINAL past MAXINT compares as signed; AND/OR are eager;
     REAL widens to binary64; unchecked ARRAY indexing (no DA/DB);
     NIL dereference reads 0 (no static check, no VM trap yet);
     CHAR/BOOLEAN arrays byte-packed (1 byte/elem, slots over-
     allocated 8x); at most 64 procedures, 64 actuals
     per call, 16 names per FP-section, 8-deep nested calls,
     8-deep WITH, 1024 slots max per type. *)

IMPORT SymTab, MGen;

CHARACTERS
  eol      = CHR(13) .
  letter   = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" .
  digit    = "0123456789" .
  hexDigit = digit + "ABCDEF" .
  noQuote1 = ANY - "'" - eol .
  noQuote2 = ANY - '"' - eol .

IGNORE CHR(9) .. CHR(13)

COMMENTS
  FROM "(*" TO "*)" NESTED

TOKENS
  ident   = letter { letter | digit } .
  integer = digit { digit }
          | digit { digit } CONTEXT("..")
          | digit { hexDigit } "H" .
  real    = digit { digit } "." { digit }
            [ "E" [ "+" | "-" ] digit { digit } ] .
  string  = "'" { noQuote1 } "'"
          | '"' { noQuote2 } '"' .

PRODUCTIONS
  M2c                                   (. VAR m1, m2: SymTab.Name; .)
    = "MODULE"
      GetIdent<m1>                      (. SymTab.Init; MGen.OpenModule(m1);
                                           IF ~SymTab.Enter(m1, SymTab.KindModule)
                                           THEN SemError(200) END .)
      ";"
      { Import } Block<FALSE> GetIdent<m2>
                                        (. IF ~SymTab.Equal(m1, m2)
                                           THEN SemError(202) END .)
      "."                               (. IF SymTab.AnyForward() THEN
                                           SemError(231)
                                         END;
                                         MGen.EndModule;
                                         SymTab.PrintTable; .) .
  Import                                (. VAR n: SymTab.Name; .)
    = "FROM"
      GetIdent<n>                       (. IF ~SymTab.Enter(n, SymTab.KindImport)
                                           THEN SemError(200) END .)
      "IMPORT"
      ImportList ";"
    | "IMPORT"
      ImportList ";" .
  ImportList                            (. VAR n: SymTab.Name; .)
    = GetIdent<n>                       (. IF ~SymTab.Enter(n, SymTab.KindImport)
                                           THEN SemError(200) END .)
      { ","
        GetIdent<n>                     (. IF ~SymTab.Enter(n, SymTab.KindImport)
                                           THEN SemError(200) END .) } .
  Block <isProc: BOOLEAN>               (. VAR began: BOOLEAN; .)
    =                                   (. began := FALSE; .)
      { Declaration }
      [ "BEGIN"                         (. began := TRUE;
                                           IF isProc THEN
                                             MGen.ProcEntry(
                                               SymTab.CurProc(),
                                               SymTab.ProcNLocals())
                                           ELSE MGen.BeginBody
                                           END; .)
        StatSeq ]
      "END"                             (. IF isProc THEN
                                           IF ~began THEN
                                             MGen.ProcEntry(
                                               SymTab.CurProc(),
                                               SymTab.ProcNLocals())
                                           END;
                                           IF SymTab.InFunction() THEN
                                             MGen.PushInt(0)
                                           END;
                                           MGen.Leave(SymTab.CurNPar(),
                                             SymTab.InFunction())
                                         END; .) .
  Declaration = "CONST"
                          {
                            ConstDecl ";" }
              | "TYPE"
                          {
                            TypeDecl ";" }
              | "VAR"
                          {
                            VarDecl ";" }
              | ProcedureDecl ";" .
  ConstDecl                             (. VAR n: SymTab.Name;
                                             t: SymTab.TypeIndex;
                                             lx: MGen.LitStr;
                                             cls: INTEGER; .)
    = GetIdent<n>                       (. IF ~SymTab.Enter(n, SymTab.KindConst)
                                           THEN SemError(200) END .)
      "="                               (. MGen.NoEmitEnter; .)
      ConstExpr<t, lx>                  (. SymTab.SetSymType(n, t);
                                           cls := SymTab.ClassOf(t);
                                           IF cls = SymTab.ClStr THEN
                                             SemError(230)
                                           ELSIF ~MGen.IsLit(lx) THEN
                                             SemError(230)
                                           END;
                                           MGen.DeclConst(n, lx, t);
                                           MGen.NoEmitExit; .) .
  ConstExpr <VAR t: SymTab.TypeIndex; VAR lx: MGen.LitStr>
                                        (. VAR vD: BOOLEAN;
                                             vnD: SymTab.Name; .)
    = Expr<t, lx, vD, vnD> .
  TypeDecl                              (. VAR n: SymTab.Name;
                                             t0, t1: SymTab.TypeIndex; .)
    = GetIdent<n>                       (. IF ~SymTab.Enter(n, SymTab.KindType)
                                           THEN SemError(200) END;
                                           t0 := SymTab.NewAlias();
                                           SymTab.SetSymType(n, t0); .)
      "="
      Type<t1>                          (. IF t1 = t0 THEN SemError(223);
                                             SymTab.SetTarget(t0,
                                               SymTab.InvalidType)
                                           ELSE SymTab.SetTarget(t0, t1) END; .) .
  VarDecl                               (. VAR t: SymTab.TypeIndex;
                                             i: CARDINAL;
                                             nm: SymTab.Name;
                                             cls: INTEGER;
                                             sl: CARDINAL; .)
    = VarIdents ":"
      Type<t>                           (. cls := SymTab.ClassOf(t);
                                           IF (cls # SymTab.ClInt)
                                              & (cls # SymTab.ClReal)
                                              & (cls # SymTab.ClBool)
                                              & (cls # SymTab.ClChar)
                                              & (cls # SymTab.ClEnum)
                                              & (cls # SymTab.ClSet)
                                              & (cls # SymTab.ClArray)
                                              & (cls # SymTab.ClRecord)
                                              & (cls # SymTab.ClPtr) THEN
                                             SemError(230)
                                           END;
                                           sl := SymTab.TypeSlots(t);
                                           IF sl = 0 THEN
                                             SemError(230);
                                             sl := 1
                                           END;
                                           i := 0;
                                           WHILE i < SymTab.PendCount() DO
                                             SymTab.PendName(i, nm);
                                             IF SymTab.SymDepth(nm) = 0 THEN
                                               MGen.DeclVarSized(nm, sl)
                                             END;
                                             INC(i)
                                           END;
                                           SymTab.FixPending(t); .) .
  VarIdents                             (. VAR n: SymTab.Name; .)
    = GetIdent<n>                       (. IF ~SymTab.EnterPending(n,
                                             SymTab.KindVar)
                                           THEN SemError(200) END .)
      { ","
        GetIdent<n>                     (. IF ~SymTab.EnterPending(n,
                                             SymTab.KindVar)
                                           THEN SemError(200) END .) } .
  ProcedureDecl                         (. VAR n, m: SymTab.Name;
                                             rt: SymTab.TypeIndex;
                                             hasR, ok: BOOLEAN;
                                             endL: INTEGER; .)
    = "PROCEDURE"                       (. hasR := FALSE; .)
      GetIdent<n>                       (. IF SymTab.IsForward(n) THEN
                                             SymTab.ReuseProc(n)
                                           ELSIF ~SymTab.EnterProc(n) THEN
                                             SemError(200)
                                           END;
                                           SymTab.OpenProcScope;
                                           endL := MGen.NewLabel();
                                           MGen.Jmp(endL); .)
      [ "(" FormalParams ")" ]
      [ ":" QualIdent<rt>               (. hasR := TRUE; .) ]
                                        (. IF hasR THEN
                                             ok := SymTab.SetProcRet(rt)
                                           ELSE
                                             ok := SymTab.SetProcRet(
                                                     SymTab.InvalidType)
                                           END;
                                           IF ~ok THEN SemError(231) END;
                                           IF ~SymTab.VerifyProc() THEN
                                             SemError(231)
                                           END; .)
      ";"
      ( Block<TRUE> GetIdent<m>         (. IF ~SymTab.Equal(n, m) THEN
                                           SemError(202) END;
                                           MGen.DefLabel(endL);
                                           SymTab.CloseProc; .)
      | "FORWARD"                     (. SymTab.SetForward;
                                           SymTab.CloseProc;
                                           MGen.DefLabel(endL); .) ) .
  FormalParams = FPSection { ";" FPSection } .
  FPSection                             (. VAR isV: BOOLEAN;
                                             nn, i: CARDINAL;
                                             pn: ARRAY [0 .. 15] OF SymTab.Name;
                                             n: SymTab.Name;
                                             t: SymTab.TypeIndex; .)
    =                                   (. isV := FALSE; nn := 0; .)
      [ "VAR"                           (. isV := TRUE; .) ]
      GetIdent<n>                       (. IF nn <= HIGH(pn) THEN
                                             MGen.CopyName(n, pn[nn])
                                           END;
                                           INC(nn); .)
      { "," GetIdent<n>                 (. IF nn <= HIGH(pn) THEN
                                             MGen.CopyName(n, pn[nn])
                                           END;
                                           INC(nn); .) }
      ":" Type<t>                       (. IF ~isV
                                              & (t # SymTab.InvalidType)
                                              & (SymTab.TypeSlots(t) > 1) THEN
                                             SemError(230)
                                           END;
                                           i := 0;
                                           WHILE i < nn DO
                                             IF i <= HIGH(pn) THEN
                                               IF ~SymTab.EnterParam(
                                                    pn[i], isV, t) THEN
                                                 SemError(200)
                                               END
                                             END;
                                             INC(i)
                                           END; .) .
  QualIdent <VAR t: SymTab.TypeIndex>
                                        (. VAR n, m: SymTab.Name; .)
    = GetIdent<n>                       (. IF ~SymTab.Lookup(n) THEN
                                             SemError(201);
                                             t := SymTab.InvalidType
                                           ELSIF (SymTab.SymKind(n) #
                                                  SymTab.KindType)
                                             & (SymTab.SymKind(n) #
                                                SymTab.KindPredef)
                                             & (SymTab.SymKind(n) #
                                                SymTab.KindImport) THEN
                                             SemError(221);
                                             t := SymTab.InvalidType
                                           ELSE t := SymTab.SymType(n) END; .)
      { "."
        GetIdent<m>                     (. t := SymTab.InvalidType; .) } .

  (* Types: ProcedureType removed; subrange factored for LL(1) *)
  Type <VAR t: SymTab.TypeIndex>
    = SimpleType<t> | ArrayType<t> | RecordType<t>
    | SetType<t> | PointerType<t> .
  SimpleType <VAR t: SymTab.TypeIndex>
                                        (. VAR t1, t2: SymTab.TypeIndex;
                                             lx1, lx2: MGen.LitStr;
                                             vD: BOOLEAN;
                                             vnD: SymTab.Name;
                                             loI, hiI: INTEGER;
                                             lok, hik: BOOLEAN; .)
    = QualIdent<t> [ "["
                      (. MGen.NoEmitEnter; lok := FALSE; hik := FALSE;
                         loI := 0; hiI := -1; .)
                      ConstExpr<t1, lx1> (. IF (t1 # SymTab.InvalidType)
                                            & (SymTab.ClassOf(t1) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(t1) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(t1) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END; .)
                      ".."
                      ConstExpr<t2, lx2> (. IF (t2 # SymTab.InvalidType)
                                            & (SymTab.ClassOf(t2) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(t2) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(t2) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END; .)
                      "]"
                                     (. IF (t1 # SymTab.InvalidType)
                                         & (t2 # SymTab.InvalidType) THEN
                                           IF MGen.IsLit(lx1) THEN
                                             IF SymTab.ClassOf(t1)
                                                = SymTab.ClChar THEN
                                               loI := MGen.CharOrd(lx1);
                                               lok := TRUE
                                             ELSIF MGen.ParseInt(lx1, loI) THEN
                                               lok := TRUE
                                             END
                                           END;
                                           IF MGen.IsLit(lx2) THEN
                                             IF SymTab.ClassOf(t2)
                                                = SymTab.ClChar THEN
                                               hiI := MGen.CharOrd(lx2);
                                               hik := TRUE
                                             ELSIF MGen.ParseInt(lx2, hiI) THEN
                                               hik := TRUE
                                             END
                                           END
                                         END;
                                        IF lok & hik THEN
                                          t := SymTab.NewSubB(t1, loI, hiI)
                                        ELSE
                                          t := SymTab.NewSub(t1);
                                          IF (t1 # SymTab.InvalidType)
                                             & (t2 # SymTab.InvalidType) THEN
                                            SemError(230)
                                          END
                                        END;
                                        MGen.NoEmitExit; .) ]
    | "["                               (. MGen.NoEmitEnter; lok := FALSE;
                                           hik := FALSE; loI := 0; hiI := -1; .)
      ConstExpr<t1, lx1>                (. IF (t1 # SymTab.InvalidType)
                                            & (SymTab.ClassOf(t1) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(t1) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(t1) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END; .)
      ".."
      ConstExpr<t2, lx2>                (. IF (t2 # SymTab.InvalidType)
                                            & (SymTab.ClassOf(t2) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(t2) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(t2) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END; .)
      "]"                               (. IF (t1 # SymTab.InvalidType)
                                           & (t2 # SymTab.InvalidType) THEN
                                             IF MGen.IsLit(lx1) THEN
                                               IF SymTab.ClassOf(t1)
                                                  = SymTab.ClChar THEN
                                                 loI := MGen.CharOrd(lx1);
                                                 lok := TRUE
                                               ELSIF MGen.ParseInt(lx1,
                                                         loI) THEN
                                                 lok := TRUE
                                               END
                                             END;
                                             IF MGen.IsLit(lx2) THEN
                                               IF SymTab.ClassOf(t2)
                                                  = SymTab.ClChar THEN
                                                 hiI := MGen.CharOrd(lx2);
                                                 hik := TRUE
                                               ELSIF MGen.ParseInt(lx2,
                                                         hiI) THEN
                                                 hik := TRUE
                                               END
                                             END
                                           END;
                                          IF lok & hik THEN
                                            t := SymTab.NewSubB(t1, loI, hiI)
                                          ELSE
                                            t := SymTab.NewSub(t1);
                                            IF (t1 # SymTab.InvalidType)
                                               & (t2 # SymTab.InvalidType) THEN
                                              SemError(230)
                                            END
                                          END;
                                           MGen.NoEmitExit; .)
    | Enum<t> .
  Enum <VAR t: SymTab.TypeIndex>
                                        (. VAR n: SymTab.Name;
                                             ord: INTEGER; .)
    = "("                               (. t := SymTab.NewEnum();
                                           ord := 0; .)
      GetIdent<n>                       (. IF ~SymTab.Enter(n,
                                             SymTab.KindConst)
                                           THEN SemError(200) END;
                                           SymTab.SetSymType(n, t);
                                           SymTab.EnumAdd(t);
                                           MGen.DeclConstInt(n, ord);
                                           INC(ord); .)
      { ","
        GetIdent<n>                     (. IF ~SymTab.Enter(n,
                                             SymTab.KindConst)
                                           THEN SemError(200) END;
                                           SymTab.SetSymType(n, t);
                                           SymTab.EnumAdd(t);
                                           MGen.DeclConstInt(n, ord);
                                           INC(ord); .) }
      ")" .
  ArrayType <VAR t: SymTab.TypeIndex>
                                        (. VAR s, s2, e: SymTab.TypeIndex;
                                             idx: ARRAY [0 .. 7] OF
                                               SymTab.TypeIndex;
                                             nc, kk: CARDINAL;
                                             loA, hiA: INTEGER; .)
    = "ARRAY"
      SimpleType<s>                     (. IF (s # SymTab.InvalidType)
                                            & (SymTab.ClassOf(s) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(s) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(s) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END;
                                           nc := 0;
                                           idx[nc] := s; INC(nc); .)
      { ","
        SimpleType<s2>                  (. IF (s2 # SymTab.InvalidType)
                                            & (SymTab.ClassOf(s2) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(s2) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(s2) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END;
                                           IF nc <= HIGH(idx) THEN
                                             idx[nc] := s2; INC(nc)
                                           END; .) }
      "OF"
      Type<e>                           (. t := e;
                                           kk := nc;
                                           WHILE kk > 0 DO
                                             DEC(kk);
                                             loA := SymTab.TypeLo(idx[kk]);
                                             hiA := SymTab.TypeHi(idx[kk]);
                                             IF SymTab.TypeLen(idx[kk]) = 0 THEN
                                               IF idx[kk]
                                                  # SymTab.InvalidType THEN
                                                 SemError(230)
                                               END;
                                               loA := 0; hiA := -1
                                             END;
                                             t := SymTab.NewArrayB(t,
                                                     loA, hiA)
                                           END; .) .
  RecordType <VAR t: SymTab.TypeIndex>
    = "RECORD"                          (. t := SymTab.NewRecord(); .)
      FieldSeq<t>
      "END" .
  FieldSeq <rt: SymTab.TypeIndex>
    = Field<rt> { ";"
                  Field<rt> } .
  Field <rt: SymTab.TypeIndex>
                                        (. VAR et: SymTab.TypeIndex; .)
    = [ FieldIdents<rt> ":"
        Type<et>                       (. SymTab.FixPendingF(rt, et); .) ] .
  FieldIdents <rt: SymTab.TypeIndex>
                                        (. VAR n: SymTab.Name; .)
    = GetIdent<n>                       (. IF ~SymTab.FieldPending(rt, n)
                                           THEN SemError(200) END .)
      { ","
        GetIdent<n>                     (. IF ~SymTab.FieldPending(rt, n)
                                           THEN SemError(200) END .) } .
  SetType <VAR t: SymTab.TypeIndex>
                                        (. VAR s: SymTab.TypeIndex; .)
    = "SET"
      "OF"
      SimpleType<s>                     (. IF (s # SymTab.InvalidType)
                                            & (SymTab.ClassOf(s) #
                                               SymTab.ClInt)
                                            & (SymTab.ClassOf(s) #
                                               SymTab.ClChar)
                                            & (SymTab.ClassOf(s) #
                                               SymTab.ClEnum) THEN
                                            SemError(224) END;
                                           t := SymTab.NewSet(s); .) .
  PointerType <VAR t: SymTab.TypeIndex>
                                        (. VAR b: SymTab.TypeIndex; .)
    = "POINTER"
      "TO"
      Type<b>                           (. t := SymTab.NewPtr(b); .) .

  (* Statements: RETURN added; calls via AssignOrCall *)
  StatSeq    = Stat { ";"
                     Stat } .
  Stat                                  (. VAR lx: INTEGER; .)
    = [ AssignOrCall | IfStat | CaseStat | WhileStat
      | RepeatStat | LoopStat | ForStat | WithStat | ReturnStat
      | NewStat | DispStat
      | "EXIT"                 (. IF MGen.TopLoop(lx) THEN
                                    MGen.Jmp(lx)
                                  ELSE SemError(230) END; .) ] .
  AssignOrCall                          (. VAR dt, et: SymTab.TypeIndex;
                                             dk: INTEGER;
                                             bn: SymTab.Name;
                                             lxD, lxe: MGen.LitStr;
                                             vE: BOOLEAN;
                                             vnE: SymTab.Name;
                                             sfx: BOOLEAN;
                                             okC: BOOLEAN;
                                             isR, conv,
                                             storable, pushedDst,
                                             pushedFld: BOOLEAN;
                                             dstBytes, srcBytes: CARDINAL;
                                             elemDt: SymTab.TypeIndex; .)
    =                                   (. sfx := FALSE; pushedDst := FALSE;
                                           pushedFld := FALSE; .)
      DesignHead<dt, dk, bn, FALSE, lxD>
      ( DesignTail<dt, dk, bn, FALSE, lxD, sfx> ":="
                                        (. storable :=
                                             (dk = SymTab.KindVar)
                                             OR (dk = SymTab.KindParam)
                                             OR (dk = SymTab.KindVarPar);
                                           IF (dk = SymTab.KindField)
                                              & (~sfx)
                                              & (dt # SymTab.InvalidType) THEN
                                             MGen.WithAddr(bn);
                                             pushedFld := TRUE
                                           END;
                                           IF storable & ~sfx
                                              & (dt # SymTab.InvalidType)
                                              & (SymTab.ClassOf(dt)
                                                 = SymTab.ClArray) THEN
                                             elemDt := SymTab.ArrayElem(dt);
                                             IF SymTab.ClassOf(elemDt)
                                                = SymTab.ClChar THEN
                                               MGen.PushAddr(bn);
                                               pushedDst := TRUE
                                             END
                                           END;
                                           IF storable & ~sfx
                                              & ~pushedDst THEN
                                             IF (dt # SymTab.InvalidType)
                                                & (SymTab.TypeSlots(dt)
                                                   > 1) THEN
                                             ELSE MGen.StoreSetup(bn)
                                             END
                                           END; .)
        Expr<et, lxe, vE, vnE>                                                  (. IF (dt # SymTab.InvalidType)
                                           & (dk # SymTab.KindVar)
                                           & (dk # SymTab.KindParam)
                                           & (dk # SymTab.KindVarPar)
                                           & (dk # SymTab.KindField)
                                           & (dk # SymTab.KindImport) THEN
                                           SemError(210)
                                         ELSIF pushedDst THEN
                                           IF et = SymTab.InvalidType THEN
                                             MGen.Drop; MGen.Drop
                                           ELSIF (SymTab.ClassOf(et)
                                                 # SymTab.ClStr) THEN
                                             SemError(230);
                                             MGen.Drop; MGen.Drop
                                           ELSE
                                             srcBytes :=
                                               MGen.StrLenOf(lxe) + 1;
                                             dstBytes :=
                                               SymTab.TypeSlots(dt) * 8;
                                             IF srcBytes > dstBytes THEN
                                               SemError(210);
                                               MGen.Drop; MGen.Drop
                                             ELSE
                                               MGen.PushBytes(srcBytes);
                                               MGen.CopyBlock
                                             END
                                           END
                                         ELSIF pushedFld THEN
                                           IF et = SymTab.InvalidType THEN
                                             MGen.Drop; MGen.Drop
                                           ELSIF (SymTab.TypeSlots(dt) > 1) THEN
                                             IF (SymTab.ClassOf(dt)
                                                = SymTab.ClArray)
                                                & (SymTab.ClassOf(
                                                   SymTab.ArrayElem(dt))
                                                   = SymTab.ClChar)
                                                & (SymTab.ClassOf(et)
                                                   = SymTab.ClStr) THEN
                                               srcBytes :=
                                                 MGen.StrLenOf(lxe) + 1;
                                               dstBytes :=
                                                 SymTab.TypeSlots(dt) * 8;
                                               IF srcBytes > dstBytes THEN
                                                 SemError(210);
                                                 MGen.Drop; MGen.Drop
                                               ELSE
                                                 MGen.PushBytes(srcBytes);
                                                 MGen.CopyBlock
                                               END
                                             ELSIF ~SymTab.Assignable(et,
                                                       dt) THEN
                                               SemError(210);
                                               MGen.Drop; MGen.Drop
                                             ELSE
                                               SemError(230);
                                               MGen.Drop; MGen.Drop
                                             END
                                           ELSE
                                             IF ~SymTab.Assignable(et,
                                                       dt) THEN
                                               SemError(210);
                                               MGen.Drop; MGen.Drop
                                             ELSE
                                               isR :=
                                                 (SymTab.ClassOf(dt)
                                                  = SymTab.ClReal);
                                               conv := isR
                                                 & SymTab.IsIntFamily(et);
                                               IF conv THEN
                                                 MGen.IntToReal
                                               END;
                                               IF (SymTab.ClassOf(dt)
                                                  = SymTab.ClChar)
                                                  OR (SymTab.ClassOf(dt)
                                                     = SymTab.ClBool) THEN
                                                 MGen.StoreByte
                                               ELSE MGen.StoreIndir0
                                               END
                                             END
                                           END
                                         ELSIF (dt # SymTab.InvalidType)
                                           & ~sfx
                                           & (SymTab.TypeSlots(dt) > 1) THEN
                                           IF ~SymTab.Assignable(et, dt) THEN
                                             SemError(210)
                                           ELSE SemError(230)
                                           END
                                         ELSIF ~SymTab.Assignable(et, dt) THEN
                                           SemError(210) END;
                                         IF dk = SymTab.KindImport THEN
                                           SemError(230)
                                         END;
                                         isR := (dt # SymTab.InvalidType)
                                                & ~pushedDst
                                                & ~pushedFld
                                                & (SymTab.ClassOf(dt)
                                                   = SymTab.ClReal);
                                         conv := isR
                                                 & SymTab.IsIntFamily(et);
                                         IF pushedDst THEN
                                         ELSIF pushedFld THEN
                                         ELSIF (dt # SymTab.InvalidType)
                                            & sfx THEN
                                           IF conv THEN
                                             MGen.IntToReal
                                           END;
                                           IF (SymTab.ClassOf(dt)
                                              = SymTab.ClChar)
                                              OR (SymTab.ClassOf(dt)
                                                 = SymTab.ClBool) THEN
                                             MGen.StoreByte
                                           ELSE MGen.StoreIndir0
                                           END
                                         ELSIF storable & ~sfx THEN
                                           IF (dt # SymTab.InvalidType)
                                              & (SymTab.TypeSlots(dt)
                                                 > 1) THEN
                                             MGen.Drop
                                           ELSE
                                             IF conv THEN
                                               MGen.IntToReal
                                             END;
                                             MGen.StoreFinish(bn)
                                           END
                                         ELSE MGen.Drop
                                         END; .)
      | CallTail<bn, sfx, FALSE, okC, FALSE>
      |                             (. MGen.ActBegin(bn);
                                       IF MGen.ActEnd(bn, FALSE, FALSE) # 0 THEN
                                         SemError(233)
                                       END; .) ) .
  CallTail <pn: SymTab.Name; sfx: BOOLEAN; inExpr: BOOLEAN;
            VAR ok: BOOLEAN; hasDead: BOOLEAN>
                                        (. VAR t: SymTab.TypeIndex;
                                             lx: MGen.LitStr;
                                             v: BOOLEAN;
                                             vn: SymTab.Name; .)
    = "("                               (. ok := FALSE;
                                           IF hasDead THEN MGen.Drop END;
                                           MGen.ActBegin(pn); .)
      [ Expr<t, lx, v, vn>              (. IF MGen.ActValue(t, v, vn) # 0 THEN
                                           SemError(233)
                                         END; .)
        { "," Expr<t, lx, v, vn>        (. IF MGen.ActValue(t, v, vn) # 0 THEN
                                           SemError(233)
                                         END; .) } ]
      ")"                               (. IF MGen.ActEnd(pn, sfx, inExpr) # 0
                                         THEN SemError(233)
                                         ELSE ok := TRUE
                                         END; .) .
  IfStat                                (. VAR t: SymTab.TypeIndex;
                                             lxC: MGen.LitStr;
                                             vC: BOOLEAN;
                                             vnC: SymTab.Name;
                                             elseL, endL: INTEGER;
                                             hasElse: BOOLEAN; .)
    = "IF"
      Expr<t, lxC, vC, vnC>             (. IF ~SymTab.BoolCheck(t) THEN
                                           SemError(214) END;
                                           elseL := MGen.NewLabel();
                                           endL := MGen.NewLabel();
                                           MGen.Jz(elseL);
                                           hasElse := FALSE; .)
      "THEN"
      StatSeq
      { "ELSIF"                         (. MGen.Jmp(endL);
                                           MGen.DefLabel(elseL); .)
        Expr<t, lxC, vC, vnC>           (. IF ~SymTab.BoolCheck(t) THEN
                                           SemError(214) END;
                                           elseL := MGen.NewLabel();
                                           MGen.Jz(elseL); .)
        "THEN"
        StatSeq }
      [ "ELSE"                          (. MGen.Jmp(endL);
                                           MGen.DefLabel(elseL);
                                           hasElse := TRUE; .)
        StatSeq ]
      "END"                             (. IF ~hasElse THEN
                                           MGen.DefLabel(elseL)
                                         END;
                                         MGen.DefLabel(endL); .) .
  CaseStat                              (. VAR st: SymTab.TypeIndex;
                                             lxS: MGen.LitStr;
                                             vS: BOOLEAN;
                                             vnS: SymTab.Name;
                                             tmp, endL: INTEGER; .)
    = "CASE"
      Expr<st, lxS, vS, vnS>            (. tmp := MGen.TempGlobal();
                                           MGen.StoreTemp(tmp);
                                           endL := MGen.NewLabel(); .)
      "OF"
      Case<st, tmp, endL> { "|"
                 Case<st, tmp, endL> }
      [ "ELSE"
        StatSeq ]
      "END"                             (. MGen.DefLabel(endL); .) .
  Case <sel: SymTab.TypeIndex; tmp: INTEGER; endL: INTEGER>
                                        (. VAR lB, lN: INTEGER; .)
    = [ LabelList<sel, tmp, lB, lN> ":" (. MGen.DefLabel(lB); .)
        StatSeq                         (. MGen.Jmp(endL);
                                           MGen.DefLabel(lN); .) ] .
  LabelList <sel: SymTab.TypeIndex; tmp: INTEGER;
             VAR lB: INTEGER; VAR lN: INTEGER>
    =                                   (. lB := MGen.NewLabel();
                                           lN := MGen.NewLabel(); .)
      Labels<sel, tmp, lB> { ","
                    Labels<sel, tmp, lB> }
                                        (. MGen.Jmp(lN); .) .
  Labels <sel: SymTab.TypeIndex; tmp: INTEGER; bodyL: INTEGER>
                                        (. VAR t, t2: SymTab.TypeIndex;
                                             lx1, lx2: MGen.LitStr;
                                             v1, v2: BOOLEAN;
                                             vn1, vn2: SymTab.Name;
                                             ta, tb, chunk: INTEGER;
                                             r, hasRange: BOOLEAN; .)
    = ConstExpr<t, lx1>                 (. IF ~SymTab.EqCheck(t, sel) THEN
                                           SemError(213) END;
                                           r := (SymTab.ClassOf(sel)
                                                 = SymTab.ClReal)
                                                & (SymTab.ClassOf(t)
                                                   = SymTab.ClReal);
                                           ta := MGen.TempGlobal();
                                           MGen.StoreTemp(ta);
                                           hasRange := FALSE; .)
      [ ".."
        ConstExpr<t2, lx2>              (. IF ~SymTab.EqCheck(t2, sel) THEN
                                           SemError(213) END;
                                           tb := MGen.TempGlobal();
                                           MGen.StoreTemp(tb);
                                           hasRange := TRUE; .) ]
                                        (. IF hasRange THEN
                                             MGen.LoadTemp(tmp);
                                             MGen.LoadTemp(ta);
                                             IF r THEN MGen.RealGe
                                             ELSE MGen.IGe END;
                                             MGen.LoadTemp(tmp);
                                             MGen.LoadTemp(tb);
                                             IF r THEN MGen.RealLe
                                             ELSE MGen.ILe END;
                                             MGen.And
                                           ELSE
                                             MGen.LoadTemp(tmp);
                                             MGen.LoadTemp(ta);
                                             IF r THEN MGen.RealEq
                                             ELSE MGen.Eq END
                                           END;
                                           chunk := MGen.NewLabel();
                                           MGen.Jz(chunk);
                                           MGen.Jmp(bodyL);
                                           MGen.DefLabel(chunk); .) .
  WhileStat                             (. VAR t: SymTab.TypeIndex;
                                             lxC: MGen.LitStr;
                                             vC: BOOLEAN;
                                             vnC: SymTab.Name;
                                             topL, endL: INTEGER; .)
    = "WHILE"                           (. topL := MGen.NewLabel();
                                           endL := MGen.NewLabel();
                                           MGen.DefLabel(topL); .)
      Expr<t, lxC, vC, vnC>             (. IF ~SymTab.BoolCheck(t) THEN
                                           SemError(214) END;
                                           MGen.Jz(endL); .)
      "DO"
      StatSeq
      "END"                             (. MGen.Jmp(topL);
                                           MGen.DefLabel(endL); .) .
  RepeatStat                            (. VAR t: SymTab.TypeIndex;
                                             lxC: MGen.LitStr;
                                             vC: BOOLEAN;
                                             vnC: SymTab.Name;
                                             topL: INTEGER; .)
    = "REPEAT"                          (. topL := MGen.NewLabel();
                                           MGen.DefLabel(topL); .)
      StatSeq
      "UNTIL"
      Expr<t, lxC, vC, vnC>             (. IF ~SymTab.BoolCheck(t) THEN
                                           SemError(214) END;
                                           MGen.Jz(topL); .) .
  LoopStat                              (. VAR topL, exitL: INTEGER; .)
    = "LOOP"                            (. topL := MGen.NewLabel();
                                           exitL := MGen.NewLabel();
                                           MGen.DefLabel(topL);
                                           MGen.PushLoop(exitL); .)
      StatSeq
      "END"                             (. MGen.Jmp(topL);
                                           MGen.DefLabel(exitL);
                                           MGen.PopLoop; .) .
  ForStat                               (. VAR n, lv: SymTab.Name;
                                             fk: INTEGER;
                                             lo, hi: SymTab.TypeIndex;
                                             lxLo, lxHi: MGen.LitStr;
                                             vLo, vHi: BOOLEAN;
                                             vnLo, vnHi: SymTab.Name;
                                             byV, ht: INTEGER;
                                             lTop, lChk, lEnd: INTEGER;
                                             neg, storable: BOOLEAN; .)
    = "FOR"
      GetIdent<n>                       (. IF ~SymTab.Lookup(n) THEN
                                            SemError(201);
                                            fk := -1
                                          ELSIF (SymTab.SymKind(n) #
                                                 SymTab.KindVar)
                                            & (SymTab.SymKind(n) #
                                               SymTab.KindParam)
                                            & (SymTab.SymKind(n) #
                                               SymTab.KindVarPar)
                                            & (SymTab.SymKind(n) #
                                               SymTab.KindField) THEN
                                            SemError(220);
                                            fk := -1
                                          ELSIF (SymTab.SymType(n) #
                                                 SymTab.InvalidType)
                                            & ~SymTab.IsIntFamily(
                                                SymTab.SymType(n)) THEN
                                            SemError(220);
                                            fk := -1
                                          ELSE
                                            fk := SymTab.SymKind(n)
                                          END;
                                          MGen.CopyName(n, lv);
                                          storable := (fk = SymTab.KindVar)
                                            OR (fk = SymTab.KindParam)
                                            OR (fk = SymTab.KindVarPar);
                                          IF storable THEN
                                            MGen.StoreSetup(lv)
                                          END; .)
      ":="
      Expr<lo, lxLo, vLo, vnLo>         (. IF (lo # SymTab.InvalidType)
                                           & ~SymTab.IsIntFamily(lo) THEN
                                           SemError(220) END;
                                           IF storable THEN
                                             MGen.StoreFinish(lv)
                                           ELSE MGen.Drop
                                           END; .)
      "TO"
      Expr<hi, lxHi, vHi, vnHi>         (. IF (hi # SymTab.InvalidType)
                                           & ~SymTab.IsIntFamily(hi) THEN
                                           SemError(220) END;
                                           ht := MGen.TempGlobal();
                                           MGen.StoreTemp(ht);
                                           byV := 1; neg := FALSE; .)
      [ "BY"
        ByLit<byV>                      (. neg := byV < 0; .) ]
      "DO"                              (. lTop := MGen.NewLabel();
                                           lChk := MGen.NewLabel();
                                           lEnd := MGen.NewLabel();
                                           MGen.Jmp(lChk);
                                           MGen.DefLabel(lTop); .)
      StatSeq
      "END"                             (. MGen.PushVar(lv);
                                           MGen.PushInt(byV);
                                           MGen.Add;
                                           IF storable THEN
                                             MGen.StoreFinish(lv)
                                           ELSE MGen.Drop
                                           END;
                                           MGen.DefLabel(lChk);
                                           MGen.PushVar(lv);
                                           MGen.LoadTemp(ht);
                                           IF neg THEN MGen.IGe
                                           ELSE MGen.ILe END;
                                           MGen.Jz(lEnd);
                                           MGen.Jmp(lTop);
                                           MGen.DefLabel(lEnd); .) .
  ByLit <VAR v: INTEGER>                (. VAR s: ARRAY [0 .. 255] OF CHAR; .)
    = integer                           (. LexString(s);
                                           IF ~MGen.ParseInt(s, v) THEN
                                             v := 1
                                           END; .)
    | "-" integer                       (. LexString(s);
                                           IF MGen.ParseInt(s, v) THEN
                                             v := -v
                                           ELSE v := -1
                                           END; .) .
  WithStat                              (. VAR dt: SymTab.TypeIndex;
                                             dk: INTEGER;
                                             bnW: SymTab.Name;
                                             lxW: MGen.LitStr;
                                             sfxW: BOOLEAN;
                                             pushed: BOOLEAN; .)
    = "WITH"
      DesignHead<dt, dk, bnW, FALSE, lxW>
      DesignTail<dt, dk, bnW, FALSE, lxW, sfxW>
                                      (. pushed := FALSE;
                                           IF dt = SymTab.InvalidType THEN
                                             IF sfxW THEN MGen.Drop END
                                           ELSIF SymTab.ClassOf(dt)
                                                  # SymTab.ClRecord THEN
                                             SemError(215);
                                             IF sfxW THEN MGen.Drop END
                                           ELSE
                                             IF ~sfxW THEN
                                               IF (dk
                                                  = SymTab.KindVar)
                                                  OR (dk
                                                     = SymTab.KindParam)
                                                  OR (dk
                                                  = SymTab.KindVarPar) THEN
                                                 MGen.PushAddr(bnW)
                                               ELSIF dk
                                                 = SymTab.KindField THEN
                                                 MGen.WithAddr(bnW)
                                               ELSE MGen.PushInt(0)
                                               END
                                             END;
                                             MGen.WithEnter(dt);
                                             pushed :=
                                               SymTab.PushRecord(dt);
                                             IF ~pushed THEN
                                               SemError(215)
                                             END
                                           END; .)
      "DO"
      StatSeq
      "END"                             (. IF pushed THEN
                                             SymTab.PopScope;
                                             MGen.WithExit
                                           END; .) .
  ReturnStat                            (. VAR t: SymTab.TypeIndex;
                                             lx: MGen.LitStr;
                                             v: BOOLEAN;
                                             vn: SymTab.Name;
                                             hasE, doRet, conv: BOOLEAN; .)
    = "RETURN"                          (. hasE := FALSE; .)
      [ Expr<t, lx, v, vn>              (. hasE := TRUE;
                                           doRet := FALSE;
                                           IF ~SymTab.InProc() THEN
                                             SemError(232)
                                           ELSIF ~SymTab.InFunction() THEN
                                             SemError(232)
                                           ELSIF ~SymTab.Assignable(
                                                     t, SymTab.CurRet()) THEN
                                             SemError(232)
                                           ELSE doRet := TRUE
                                           END;
                                           conv := doRet
                                                   & SymTab.IsIntFamily(t)
                                                   & (SymTab.ClassOf(
                                                        SymTab.CurRet())
                                                      = SymTab.ClReal);
                                           IF doRet THEN
                                             IF conv THEN
                                               MGen.IntToReal
                                             END;
                                             MGen.Leave(
                                               SymTab.CurNPar(), TRUE)
                                           ELSE MGen.Drop
                                           END; .) ]
                                         (. IF ~hasE THEN
                                             IF ~SymTab.InProc() THEN
                                               SemError(232)
                                             ELSIF SymTab.InFunction() THEN
                                               SemError(232)
                                             ELSE MGen.Leave(
                                               SymTab.CurNPar(), FALSE)
                                             END
                                           END; .) .
  NewStat                               (. VAR dt: SymTab.TypeIndex;
                                             dk: INTEGER;
                                             bnN: SymTab.Name;
                                             lxN: MGen.LitStr;
                                             sfxN: BOOLEAN;
                                             baseT: SymTab.TypeIndex;
                                             slN: CARDINAL; .)
    = "NEW"
      "(" DesignHead<dt, dk, bnN, FALSE, lxN>
          DesignTail<dt, dk, bnN, FALSE, lxN, sfxN>
      ")"                               (. IF dt = SymTab.InvalidType THEN
                                           IF sfxN THEN MGen.Drop END
                                         ELSIF SymTab.ClassOf(dt)
                                                # SymTab.ClPtr THEN
                                           SemError(219);
                                           IF sfxN THEN MGen.Drop END
                                         ELSE
                                           baseT := SymTab.PtrBase(dt);
                                           slN := SymTab.TypeSlots(baseT);
                                           IF slN = 0 THEN
                                             SemError(230);
                                             slN := 1
                                           END;
                                           IF ~sfxN THEN
                                             IF (dk = SymTab.KindVar)
                                                OR (dk
                                                    = SymTab.KindParam)
                                                OR (dk
                                                 = SymTab.KindVarPar) THEN
                                               MGen.PushAddr(bnN)
                                             ELSIF dk
                                               = SymTab.KindField THEN
                                               MGen.WithAddr(bnN)
                                             ELSE MGen.PushInt(0)
                                             END
                                           END;
                                           MGen.PushBytes(slN * 8);
                                           MGen.AllocOp
                                         END; .) .
  DispStat                              (. VAR dt: SymTab.TypeIndex;
                                             dk: INTEGER;
                                             bnD: SymTab.Name;
                                             lxD: MGen.LitStr;
                                             sfxD: BOOLEAN;
                                             baseT: SymTab.TypeIndex;
                                             slD: CARDINAL; .)
    = "DISPOSE"
      "(" DesignHead<dt, dk, bnD, FALSE, lxD>
          DesignTail<dt, dk, bnD, FALSE, lxD, sfxD>
      ")"                               (. IF dt = SymTab.InvalidType THEN
                                           IF sfxD THEN MGen.Drop END
                                         ELSIF SymTab.ClassOf(dt)
                                                # SymTab.ClPtr THEN
                                           SemError(219);
                                           IF sfxD THEN MGen.Drop END
                                         ELSE
                                           baseT := SymTab.PtrBase(dt);
                                           slD := SymTab.TypeSlots(baseT);
                                           IF slD = 0 THEN
                                             SemError(230);
                                             slD := 1
                                           END;
                                           IF ~sfxD THEN
                                             IF (dk = SymTab.KindVar)
                                                OR (dk
                                                    = SymTab.KindParam)
                                                OR (dk
                                                 = SymTab.KindVarPar) THEN
                                               MGen.PushAddr(bnD)
                                             ELSIF dk
                                               = SymTab.KindField THEN
                                               MGen.WithAddr(bnD)
                                             ELSE MGen.PushInt(0)
                                             END
                                           END;
                                           MGen.PushBytes(slD * 8);
                                           MGen.DeallocOp
                                         END; .) .

  (* Expressions: Designator without ActualParameters (calls use
     CallTail). Each expression synthesizes its SymTab type in t,
     the source text in lx for single literals ("" otherwise), and
     whether it is a plain variable (v/vn) for VAR actuals.
     Values travel on the MC64 stack. *)
  DesignHead <VAR t: SymTab.TypeIndex; VAR k: INTEGER;
              VAR bn: SymTab.Name; doLoad: BOOLEAN; VAR lx: MGen.LitStr>
                                        (. VAR n: SymTab.Name;
                                             cls: INTEGER; .)
    = GetIdent<n>                       (. MGen.CopyName(n, bn);
                                           lx[0] := 0C;
                                           IF ~SymTab.Lookup(n) THEN
                                             SemError(201);
                                             t := SymTab.InvalidType; k := -1;
                                             IF doLoad THEN
                                               MGen.PushInt(0)
                                             END
                                           ELSE
                                             t := SymTab.SymType(n);
                                             k := SymTab.SymKind(n);
                                             IF k = SymTab.KindConst THEN
                                               IF SymTab.Equal(n, "TRUE") THEN
                                                 t := SymTab.BoolType();
                                                 MGen.CopyName("TRUE", lx);
                                                 IF doLoad THEN
                                                   MGen.PushInt(1)
                                                 END
                                               ELSIF SymTab.Equal(n,
                                                       "FALSE") THEN
                                                 t := SymTab.BoolType();
                                                 MGen.CopyName("FALSE", lx);
                                                 IF doLoad THEN
                                                   MGen.PushInt(0)
                                                 END
                                               ELSE
                                                 cls :=
                                                   SymTab.ClassOf(t);
                                                 IF (t #
                                                     SymTab.InvalidType)
                                                    & (cls # SymTab.ClStr)
                                                    & ((cls = SymTab.ClInt)
                                                    OR (cls = SymTab.ClReal)
                                                    OR (cls = SymTab.ClBool)
                                                    OR (cls = SymTab.ClChar)
                                                    OR (cls
                                                        = SymTab.ClEnum)) THEN
                                                   IF doLoad THEN
                                                     MGen.LoadVar(n)
                                                   END
                                                 ELSIF doLoad THEN
                                                   MGen.PushInt(0)
                                                 END
                                               END
                                              ELSIF (k = SymTab.KindVar)
                                                 OR (k = SymTab.KindParam)
                                                 OR (k
                                                     = SymTab.KindVarPar) THEN
                                                cls := SymTab.ClassOf(t);
                                                IF (cls = SymTab.ClInt)
                                                   OR (cls = SymTab.ClReal)
                                                   OR (cls = SymTab.ClBool)
                                                   OR (cls = SymTab.ClChar)
                                                   OR (cls
                                                       = SymTab.ClEnum)
                                                   OR (cls
                                                       = SymTab.ClSet)
                                                   OR (cls
                                                       = SymTab.ClPtr) THEN
                                                  IF doLoad THEN
                                                    MGen.PushVar(n)
                                                  END
                                                ELSIF (cls
                                                       = SymTab.ClArray)
                                                   OR (cls
                                                       = SymTab.ClRecord) THEN
                                                  IF doLoad THEN
                                                    MGen.PushAddr(n)
                                                  END
                                                ELSIF t
                                                  = SymTab.InvalidType THEN
                                                  IF doLoad THEN
                                                    MGen.PushInt(0)
                                                  END
                                                ELSE SemError(230);
                                                  IF doLoad THEN
                                                    MGen.PushInt(0)
                                                  END
                                                END
                                             ELSE
                                               IF doLoad THEN
                                                 IF k = SymTab.KindField THEN
                                                   MGen.WithAddr(n);
                                                   cls := SymTab.ClassOf(t);
                                                   IF (t
                                                      = SymTab.InvalidType)
                                                      OR (cls
                                                         = SymTab.ClArray)
                                                      OR (cls
                                                         = SymTab.ClRecord) THEN
                                                   ELSE
                                                     IF (cls
                                                        = SymTab.ClChar)
                                                        OR (cls
                                                           = SymTab.ClBool) THEN
                                                       MGen.LoadByte
                                                     ELSE MGen.LoadIndir
                                                     END
                                                   END
                                                 ELSE MGen.PushInt(0)
                                                 END
                                               END;
                                               IF k = SymTab.KindField THEN
                                               ELSIF k
                                                     = SymTab.KindImport THEN
                                                 SemError(230)
                                               END
                                             END
                                           END; .) .
  DesignTail <VAR t: SymTab.TypeIndex; VAR k: INTEGER;
              VAR bn: SymTab.Name; doLoad: BOOLEAN; VAR lx: MGen.LitStr;
              VAR sfx: BOOLEAN>
                                        (. VAR m: SymTab.Name;
                                             it: SymTab.TypeIndex;
                                             lxI: MGen.LitStr;
                                             vI: BOOLEAN;
                                             vnI: SymTab.Name;
                                             loA: INTEGER;
                                             elemT: SymTab.TypeIndex;
                                             esl, ebytes: CARDINAL;
                                             firstT: BOOLEAN;
                                             clsI: INTEGER; .)
    =                                   (. sfx := FALSE; .)
      { "."                             (. firstT := ~sfx;
                                           sfx := TRUE; lx[0] := 0C;
                                           IF ~doLoad & firstT THEN
                                             IF (k = SymTab.KindVar)
                                                OR (k = SymTab.KindParam)
                                                OR (k
                                                    = SymTab.KindVarPar) THEN
                                               MGen.PushAddr(bn)
                                             ELSIF k
                                               = SymTab.KindField THEN
                                               MGen.WithAddr(bn)
                                             ELSE MGen.PushInt(0)
                                             END
                                           END; .)
        GetIdent<m>                     (. IF t = SymTab.InvalidType THEN
                                             IF ~doLoad & firstT THEN
                                               MGen.Drop
                                             ELSIF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             END
                                           ELSIF SymTab.ClassOf(t) #
                                                 SymTab.ClRecord THEN
                                             SemError(215);
                                             t := SymTab.InvalidType;
                                             IF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             ELSIF firstT THEN
                                               MGen.Drop
                                             END
                                           ELSIF ~SymTab.FieldExists(t, m) THEN
                                             SemError(216);
                                             t := SymTab.InvalidType;
                                             IF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             ELSIF firstT THEN
                                               MGen.Drop
                                             END
                                           ELSE
                                             loA := SymTab.FieldOffset(t, m);
                                             elemT := SymTab.FieldType(t, m);
                                             IF loA < 0 THEN
                                               SemError(216);
                                               t := SymTab.InvalidType;
                                               IF doLoad THEN
                                                 MGen.Drop; MGen.PushInt(0)
                                               ELSIF firstT THEN
                                                 MGen.Drop
                                               END
                                             ELSE
                                               MGen.FieldAdd(
                                                 VAL(CARDINAL, loA));
                                               t := elemT
                                             END
                                           END; .)
      | "["                             (. firstT := ~sfx;
                                           sfx := TRUE; lx[0] := 0C;
                                           IF ~doLoad & firstT THEN
                                             IF (k = SymTab.KindVar)
                                                OR (k = SymTab.KindParam)
                                                OR (k
                                                    = SymTab.KindVarPar) THEN
                                               MGen.PushAddr(bn)
                                             ELSIF k
                                               = SymTab.KindField THEN
                                               MGen.WithAddr(bn)
                                             ELSE MGen.PushInt(0)
                                             END
                                           END; .)
        Expr<it, lxI, vI, vnI>          (. IF t = SymTab.InvalidType THEN
                                           MGen.Drop;
                                           IF doLoad THEN
                                             MGen.Drop; MGen.PushInt(0)
                                           ELSE
                                             IF ~firstT THEN
                                             ELSE MGen.Drop
                                             END
                                           END
                                         ELSIF SymTab.ClassOf(t) #
                                                 SymTab.ClArray THEN
                                           SemError(217);
                                           t := SymTab.InvalidType;
                                           MGen.Drop;
                                           IF doLoad THEN
                                             MGen.Drop; MGen.PushInt(0)
                                           ELSE
                                             IF ~firstT THEN
                                             ELSE MGen.Drop
                                             END
                                           END
                                         ELSE
                                           clsI := SymTab.ClassOf(it);
                                           IF (it
                                              # SymTab.InvalidType)
                                              & (clsI # SymTab.ClInt)
                                              & (clsI # SymTab.ClChar)
                                              & (clsI # SymTab.ClEnum)
                                              & (clsI
                                                 # SymTab.ClBool) THEN
                                             SemError(218);
                                             t := SymTab.InvalidType;
                                             MGen.Drop;
                                             IF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             ELSE
                                               IF ~firstT THEN
                                               ELSE MGen.Drop
                                               END
                                             END
                                           ELSE
                                             loA := SymTab.ArrayLo(t);
                                             elemT := SymTab.ArrayElem(t);
                                             esl := SymTab.TypeSlots(elemT);
                                             IF esl = 0 THEN
                                               SemError(230);
                                               esl := 1
                                             END;
                                             IF (SymTab.ClassOf(elemT)
                                                = SymTab.ClChar)
                                                OR (SymTab.ClassOf(elemT)
                                                   = SymTab.ClBool) THEN
                                               ebytes := 1
                                             ELSE ebytes := esl * 8
                                             END;
                                             MGen.IdxScale(loA, ebytes);
                                             t := elemT
                                           END
                                         END; .)
        { ","
          Expr<it, lxI, vI, vnI>        (. IF t = SymTab.InvalidType THEN
                                           MGen.Drop;
                                           IF doLoad THEN
                                             MGen.Drop; MGen.PushInt(0);
                                             t := SymTab.InvalidType
                                           END
                                         ELSIF SymTab.ClassOf(t) #
                                                 SymTab.ClArray THEN
                                           SemError(217);
                                           t := SymTab.InvalidType;
                                           MGen.Drop;
                                           IF doLoad THEN
                                             MGen.Drop; MGen.PushInt(0)
                                           END
                                         ELSE
                                           clsI := SymTab.ClassOf(it);
                                           IF (it
                                              # SymTab.InvalidType)
                                              & (clsI # SymTab.ClInt)
                                              & (clsI # SymTab.ClChar)
                                              & (clsI # SymTab.ClEnum)
                                              & (clsI
                                                 # SymTab.ClBool) THEN
                                             SemError(218);
                                             t := SymTab.InvalidType;
                                             MGen.Drop;
                                             IF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             END
                                           ELSE
                                             loA := SymTab.ArrayLo(t);
                                             elemT := SymTab.ArrayElem(t);
                                             esl := SymTab.TypeSlots(elemT);
                                             IF esl = 0 THEN
                                               SemError(230);
                                               esl := 1
                                             END;
                                             IF (SymTab.ClassOf(elemT)
                                                = SymTab.ClChar)
                                                OR (SymTab.ClassOf(elemT)
                                                   = SymTab.ClBool) THEN
                                               ebytes := 1
                                             ELSE ebytes := esl * 8
                                             END;
                                             MGen.IdxScale(loA, ebytes);
                                             t := elemT
                                           END
                                         END; .) }
        "]"
      | "^"                             (. firstT := ~sfx;
                                           sfx := TRUE; lx[0] := 0C;
                                           IF ~doLoad & firstT THEN
                                             IF (k = SymTab.KindVar)
                                                OR (k = SymTab.KindParam)
                                                OR (k
                                                    = SymTab.KindVarPar) THEN
                                               MGen.PushAddr(bn)
                                             ELSIF k
                                               = SymTab.KindField THEN
                                               MGen.WithAddr(bn)
                                             ELSE MGen.PushInt(0)
                                             END
                                           END; .)
                                        (. IF t = SymTab.InvalidType THEN
                                             IF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             ELSIF firstT THEN
                                               MGen.Drop
                                             END
                                           ELSIF SymTab.ClassOf(t) #
                                                 SymTab.ClPtr THEN
                                             SemError(219);
                                             t := SymTab.InvalidType;
                                             IF doLoad THEN
                                               MGen.Drop; MGen.PushInt(0)
                                             ELSIF firstT THEN
                                               MGen.Drop
                                             END
                                           ELSE
                                             elemT := SymTab.PtrBase(t);
                                             t := elemT;
                                             IF doLoad THEN
                                               IF ~(firstT
                                                  & ((k
                                                      = SymTab.KindVar)
                                                  OR (k
                                                      = SymTab.KindParam)
                                                  OR (k
                                                      = SymTab.KindVarPar)))
                                               THEN
                                                 MGen.LoadIndir
                                               END
                                             ELSE
                                               MGen.LoadIndir
                                             END
                                           END; .) } .
  Expr <VAR t: SymTab.TypeIndex; VAR lx: MGen.LitStr;
        VAR v: BOOLEAN; VAR vn: SymTab.Name>
                                        (. VAR t2: SymTab.TypeIndex;
                                             tc, op: INTEGER;
                                             lx2: MGen.LitStr;
                                             v2: BOOLEAN;
                                             vn2: SymTab.Name;
                                             r: BOOLEAN; .)
    = SimExpr<t, lx, v, vn> [ Rel<op> SimExpr<t2, lx2, v2, vn2>
      (. lx[0] := 0C; v := FALSE;
         IF op = SymTab.OpIn THEN
           IF SymTab.InCheck(t, t2) THEN
             t := SymTab.BoolType();
             MGen.BitIn
           ELSE SemError(222);
             t := SymTab.InvalidType;
             MGen.Drop; MGen.Drop; MGen.PushInt(0)
           END
         ELSIF (t # SymTab.InvalidType)
            & (t2 # SymTab.InvalidType)
            & ((SymTab.ClassOf(t) = SymTab.ClArray)
               OR (SymTab.ClassOf(t) = SymTab.ClRecord)
               OR (SymTab.ClassOf(t2) = SymTab.ClArray)
               OR (SymTab.ClassOf(t2) = SymTab.ClRecord)) THEN
           SemError(213); t := SymTab.InvalidType;
           MGen.Drop; MGen.Drop; MGen.PushInt(0)
         ELSE
           tc := SymTab.ClassOf(t);
           IF SymTab.RelCheck(t, t2, op) THEN
             t := SymTab.BoolType()
           ELSE SemError(213); t := SymTab.InvalidType END;
           IF t # SymTab.InvalidType THEN
             r := tc = SymTab.ClReal;
             IF r THEN
               IF op = SymTab.OpEq THEN MGen.RealEq
               ELSIF (op = SymTab.OpNeq1)
                     OR (op = SymTab.OpNeq2) THEN MGen.RealNe
               ELSIF op = SymTab.OpLt THEN MGen.RealLt
               ELSIF op = SymTab.OpLe THEN MGen.RealLe
               ELSIF op = SymTab.OpGt THEN MGen.RealGt
               ELSE MGen.RealGe END
             ELSE
               IF op = SymTab.OpEq THEN MGen.Eq
               ELSIF (op = SymTab.OpNeq1)
                     OR (op = SymTab.OpNeq2) THEN MGen.Neq
               ELSIF op = SymTab.OpLt THEN MGen.ILt
               ELSIF op = SymTab.OpLe THEN MGen.ILe
               ELSIF op = SymTab.OpGt THEN MGen.IGt
               ELSE MGen.IGe END
             END
           ELSE MGen.Drop; MGen.Drop; MGen.PushInt(0)
           END
         END; .) ] .
  Rel <VAR op: INTEGER>
    = "="                     (. op := SymTab.OpEq; .)
    | "#"                     (. op := SymTab.OpNeq1; .)
    | "<>"                    (. op := SymTab.OpNeq2; .)
    | "<"                     (. op := SymTab.OpLt; .)
    | "<="                    (. op := SymTab.OpLe; .)
    | ">"                     (. op := SymTab.OpGt; .)
    | ">="                    (. op := SymTab.OpGe; .)
    | "IN"                    (. op := SymTab.OpIn; .) .
  SimExpr <VAR t: SymTab.TypeIndex; VAR lx: MGen.LitStr;
           VAR v: BOOLEAN; VAR vn: SymTab.Name>
                                        (. VAR t2, res2: SymTab.TypeIndex;
                                             op: INTEGER;
                                             lx2: MGen.LitStr;
                                             v2: BOOLEAN;
                                             vn2: SymTab.Name;
                                             neg, isR: BOOLEAN; .)
    =                                   (. neg := FALSE; .)
      [ "+" | "-"                       (. neg := TRUE; .) ]
      Term<t, lx, v, vn>                (. IF neg THEN
                                           v := FALSE;
                                           IF MGen.IsLit(lx) THEN
                                             MGen.NegFold(lx, lx)
                                           ELSE lx[0] := 0C
                                           END;
                                           IF SymTab.ClassOf(t)
                                              = SymTab.ClReal THEN
                                             MGen.NegReal
                                           ELSE MGen.NegInt
                                           END
                                         END; .)
      { AddOp<op> Term<t2, lx2, v2, vn2>
      (. lx[0] := 0C; v := FALSE;
         IF op = SymTab.OpOr THEN
           IF SymTab.BoolCheck(t) & SymTab.BoolCheck(t2) THEN
             t := SymTab.BoolType()
           ELSE SemError(212); t := SymTab.InvalidType END;
           MGen.Or
         ELSIF (t # SymTab.InvalidType)
            & (t2 # SymTab.InvalidType)
            & (SymTab.ClassOf(t) = SymTab.ClSet)
            & (SymTab.ClassOf(t2) = SymTab.ClSet) THEN
           IF op = SymTab.OpAdd THEN
             MGen.Or
           ELSE
             MGen.PushBits(0FFFFFFFFFFFFFFFFH);
             MGen.BitXor;
             MGen.And
           END
         ELSE
           IF SymTab.ArithCheck(t, t2, FALSE, res2) THEN t := res2
           ELSE SemError(211); t := SymTab.InvalidType END;
           isR := (t # SymTab.InvalidType)
                  & (SymTab.ClassOf(t) = SymTab.ClReal);
           IF op = SymTab.OpAdd THEN
             IF isR THEN MGen.RealAdd ELSE MGen.Add END
           ELSE
             IF isR THEN MGen.RealSub ELSE MGen.Sub END
           END
         END; .) } .
  AddOp <VAR op: INTEGER>
    = "+"                     (. op := SymTab.OpAdd; .)
    | "-"                     (. op := SymTab.OpSub; .)
    | "OR"                    (. op := SymTab.OpOr; .) .
  Term <VAR t: SymTab.TypeIndex; VAR lx: MGen.LitStr;
        VAR v: BOOLEAN; VAR vn: SymTab.Name>
                                        (. VAR t2, res2: SymTab.TypeIndex;
                                             op: INTEGER;
                                             lx2: MGen.LitStr;
                                             v2: BOOLEAN;
                                             vn2: SymTab.Name;
                                             isR: BOOLEAN;
                                             mt: INTEGER; .)
    = Fact<t, lx, v, vn> { MulOp<op> Fact<t2, lx2, v2, vn2>
      (. lx[0] := 0C; v := FALSE;
         IF op = SymTab.OpAnd THEN
           IF SymTab.BoolCheck(t) & SymTab.BoolCheck(t2) THEN
             t := SymTab.BoolType()
           ELSE SemError(212); t := SymTab.InvalidType END;
           MGen.And
         ELSIF (op = SymTab.OpTimes)
            & (t # SymTab.InvalidType)
            & (t2 # SymTab.InvalidType)
            & (SymTab.ClassOf(t) = SymTab.ClSet)
            & (SymTab.ClassOf(t2) = SymTab.ClSet) THEN
           MGen.And
         ELSE
           IF SymTab.ArithCheck(t, t2,
                (op = SymTab.OpDiv) OR (op = SymTab.OpMod),
                res2) THEN t := res2
           ELSE SemError(211); t := SymTab.InvalidType END;
           isR := (t # SymTab.InvalidType)
                  & (SymTab.ClassOf(t) = SymTab.ClReal);
           IF op = SymTab.OpTimes THEN
             IF isR THEN MGen.RealMul ELSE MGen.MulU END
           ELSIF op = SymTab.OpSlash THEN
             IF isR THEN MGen.RealDiv ELSE MGen.DivI END
           ELSIF op = SymTab.OpDiv THEN
             MGen.DivI
           ELSE
             mt := MGen.TempGlobal();
             MGen.ModI(mt)
           END
         END; .) } .
  MulOp <VAR op: INTEGER>
    = "*"                     (. op := SymTab.OpTimes; .)
    | "/"                     (. op := SymTab.OpSlash; .)
    | "DIV"                   (. op := SymTab.OpDiv; .)
    | "MOD"                   (. op := SymTab.OpMod; .)
    | "AND"                   (. op := SymTab.OpAnd; .)
    | "&"                     (. op := SymTab.OpAnd; .) .
  Fact <VAR t: SymTab.TypeIndex; VAR lx: MGen.LitStr;
        VAR v: BOOLEAN; VAR vn: SymTab.Name>
                                        (. VAR s: ARRAY [0 .. 255] OF CHAR;
                                             t2, et, dt, st: SymTab.TypeIndex;
                                             dk: INTEGER;
                                             bnF: SymTab.Name;
                                             lxD, lx2: MGen.LitStr;
                                             v2: BOOLEAN;
                                             vn2: SymTab.Name;
                                             vi: INTEGER;
                                             c: CARDINAL;
                                             b: LONGCARD;
                                             sfxF: BOOLEAN;
                                             okF: BOOLEAN; .)
    = integer                         (. LexString(s);
                                         MGen.CopyName(s, lx);
                                         v := FALSE;
                                         IF MGen.ParseInt(s, vi) THEN
                                           MGen.PushInt(vi)
                                         ELSIF MGen.ParseCard(s, c) THEN
                                           MGen.PushBits(
                                             VAL(LONGCARD, c))
                                         ELSE MGen.PushInt(0)
                                         END;
                                         t := SymTab.IntType(); .)
    | real                            (. LexString(s);
                                         MGen.CopyName(s, lx);
                                         v := FALSE;
                                         IF MGen.ParseReal(s, b) THEN
                                           MGen.PushBits(b)
                                         ELSE MGen.PushBits(0H)
                                         END;
                                         t := SymTab.RealType(); .)
    | string                          (. LexString(s);
                                         v := FALSE;
                                         IF SymTab.StrLen(s) <= 3 THEN
                                           t := SymTab.CharType();
                                           MGen.CopyName(s, lx);
                                           MGen.PushInt(
                                             MGen.CharOrd(s))
                                         ELSE t := SymTab.NewStr();
                                           MGen.CopyName(s, lx);
                                           MGen.EmitString(s)
                                         END; .)
    | DesignHead<dt, dk, bnF, TRUE, lxD>
      DesignTail<dt, dk, bnF, TRUE, lxD, sfxF>
                                        (. t := dt;
                                           MGen.CopyName(lxD, lx);
                                           IF sfxF
                                              & (t # SymTab.InvalidType)
                                              & (SymTab.ClassOf(t)
                                                 # SymTab.ClArray)
                                              & (SymTab.ClassOf(t)
                                                 # SymTab.ClRecord) THEN
                                             IF (SymTab.ClassOf(t)
                                                = SymTab.ClChar)
                                                OR (SymTab.ClassOf(t)
                                                   = SymTab.ClBool) THEN
                                               MGen.LoadByte
                                             ELSE MGen.LoadIndir
                                             END
                                           END;
                                           v := ~sfxF
                                                & ((dk = SymTab.KindVar)
                                                OR (dk = SymTab.KindParam)
                                                OR (dk
                                                    = SymTab.KindVarPar));
                                           MGen.CopyName(bnF, vn); .)
      [ CallTail<bnF, sfxF, TRUE, okF, TRUE>
                                        (. IF okF THEN
                                             IF SymTab.SymKind(bnF)
                                                = SymTab.KindProc THEN
                                               t := SymTab.ProcRet(bnF)
                                             ELSE
                                               t := SymTab.InvalidType
                                             END
                                           ELSE t := SymTab.InvalidType
                                           END;
                                           lx[0] := 0C; v := FALSE; .) ]
    | "("
      Expr<et, lx, v, vn> ")"         (. t := et; .)
    | ( "NOT" | "~" )
      Fact<t2, lx2, v2, vn2>          (. lx[0] := 0C; v := FALSE;
                                         IF SymTab.BoolCheck(t2) THEN
                                           t := SymTab.BoolType()
                                         ELSE SemError(212);
                                           t := SymTab.InvalidType END;
                                         MGen.Not; .)
    | SetLit<st>                      (. lx[0] := 0C; v := FALSE;
                                         t := st; .) .
  SetLit <VAR t: SymTab.TypeIndex>
                                        (. VAR first, et: SymTab.TypeIndex;
                                             lxE, lxE2: MGen.LitStr;
                                             vE, vE2: BOOLEAN;
                                             vnE, vnE2: SymTab.Name;
                                             hasR: BOOLEAN; .)
    = "{"
                                (. MGen.PushInt(0);
                                   t := SymTab.SetFor(SymTab.IntType()); .)
      [ Elem<et, lxE, lxE2, hasR>   (. first := et;
                                       t := SymTab.SetFor(et);
                                       IF hasR THEN
                                         MGen.PushInt(1); MGen.Add;
                                         MGen.FieldMask
                                       ELSE MGen.Power2 END;
                                       MGen.Or; .)
        { ","
          Elem<et, lxE, lxE2, hasR> (. IF ~SymTab.SetElemCheck(first, et) THEN
                                       SemError(222) END;
                                       IF hasR THEN
                                         MGen.PushInt(1); MGen.Add;
                                         MGen.FieldMask
                                       ELSE MGen.Power2 END;
                                       MGen.Or; .) } ]
      "}" .
  Elem <VAR t: SymTab.TypeIndex; VAR lx: MGen.LitStr;
        VAR lx2: MGen.LitStr; VAR hasR: BOOLEAN>
                                        (. VAR t2: SymTab.TypeIndex;
                                             vD, vD2: BOOLEAN;
                                             vnD, vnD2: SymTab.Name; .)
    = Expr<t, lx, vD, vnD>              (. hasR := FALSE;
                                           lx2[0] := 0C; .)
      [ ".."
        Expr<t2, lx2, vD2, vnD2>        (. IF ~SymTab.SetElemCheck(t, t2) THEN
                                           SemError(222) END;
                                           hasR := TRUE; .) ] .

  GetIdent <VAR n: SymTab.Name>
    = ident                           (. LexName(n); .) .

END M2c.