Wirth-AT-grammars/Voc/voc_oberon.lst

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

Grammar Tests:

Deletable symbols:
     DeclarationSequence
     case
     StatementSequence
     statement
     FieldList
     FieldListSequence
Undefined nonterminals:   -- none --
Unreachable nonterminals: -- none --
Circular derivations:     -- none --
Underivable nonterminals: -- none --
LL(1) conditions:
 LL(1) error in DeclarationSequence: "PROCEDURE" is the start of several alternatives.
 LL(1) error in statement: ident is the start of several alternatives.
 LL(1) error in designator: "(" is the start & successor of a deletable structure
 LL(1) error in qualident: ident is the start & successor of a deletable structure

Listing:

    1  COMPILER Oberon
    2  (* A grammar for Oberon *)
    3  
    4  CHARACTERS
    5    eol      = CHR(13) .
    6    letter   = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" .
    7    digit    = "0123456789" .
    8    hexDigit = digit + "ABCDEF" .
    9    noQuote  = ANY - '"' - eol  .
   10  
   11  IGNORE  CHR(9) .. CHR(13)
   12  
   13  COMMENTS
   14    FROM "(*" TO "*)" NESTED
   15  
   16  TOKENS
   17    ident   =  letter { letter | digit } .
   18    integer  =  digit { digit } | digit { hexDigit } "H" .
   19    real  =  digit { digit } "." { digit }
   20             [ ("E" | "D") [ "+" | "-" ] digit { digit } ] .
   21    CharConstant = digit { hexDigit } "X" .
   22    string  =  '"' { noQuote } '"' .
   23  
   24  PRODUCTIONS
   25    Oberon           =  module .
   26    number           =  integer | real .
   27    identdef         =  ident [ "*" ] .
   28    qualident        =  [ ident "." ] ident .
   29    ConstantDeclaration  =  identdef "=" ConstExpression .
   30    ConstExpression  =  expression .
   31    TypeDeclaration  =  identdef "=" type .
   32    type             =  qualident | ArrayType | RecordType | PointerType | ProcedureType .
   33    ArrayType        =  "ARRAY" length { "," length } "OF" type .
   34    length           =  ConstExpression .
   35    RecordType       =  "RECORD" [ "(" BaseType ")" ] FieldListSequence "END" .
   36    BaseType         =  qualident .
   37    FieldListSequence  =  FieldList { ";" FieldList } .
   38    FieldList        =  [ IdentList ":" type ] .
   39    IdentList        =  identdef { "," identdef } .
   40    PointerType      =  "POINTER" "TO" type .
   41    ProcedureType    =  "PROCEDURE" [ FormalParameters ] .
   42    VariableDeclaration  =  IdentList ":" type .
   43    designator       =  qualident { "." ident | "[" ExpList "]" | "(" qualident ")" | "^"  } .
   44    ExpList          =  expression { "," expression } .
   45    expression       =  SimpleExpression [ relation SimpleExpression ] .
   46    relation         =  "=" | "#" | "<" | "<=" | ">" | ">=" | "IN" | "IS" .
   47    SimpleExpression =  [ "+" | "-" ] term { AddOperator term } .
   48    AddOperator      =  "+" | "-" | "OR" .
   49    term             =  factor { MulOperator factor } .
   50    MulOperator      =  "*" | "/" | "DIV" | "MOD" | "&" .
   51    factor           =  number | CharConstant | string | "NIL" | set
   52                        | designator [ ActualParameters ]
   53                        | "(" expression ")" | "~" factor .
   54    set              =  "{" [ element { "," element } ] "}" .
   55    element          =  expression [ ".." expression ] .
   56    ActualParameters =  "(" [ ExpList ] ")" .
   57    statement        =  [ assignment | ProcedureCall | IfStatement |
   58                          CaseStatement | WhileStatement | RepeatStatement |
   59                          LoopStatement | WithStatement | "EXIT" |
   60                          "RETURN" [ expression ] ] .
   61    assignment       =  designator ":=" expression .
   62    ProcedureCall    =  designator [ ActualParameters ] .
   63    StatementSequence =  statement { ";" statement } .
   64    IfStatement      =  "IF" expression "THEN" StatementSequence
   65                       { "ELSIF" expression "THEN" StatementSequence }
   66                       [ "ELSE" StatementSequence ] "END" .
   67    CaseStatement    =  "CASE" expression "OF" case { "|" case }
   68                       [ "ELSE" StatementSequence ] "END" .
   69    case             =  [ CaseLabelList ":" StatementSequence ] .
   70    CaseLabelList    =  CaseLabels { "," CaseLabels } .
   71    CaseLabels       =  ConstExpression [ ".." ConstExpression ] .
   72    WhileStatement   =  "WHILE" expression "DO" StatementSequence "END" .
   73    RepeatStatement  =  "REPEAT" StatementSequence "UNTIL" expression .
   74    LoopStatement    =  "LOOP" StatementSequence "END" .
   75    WithStatement    =  "WITH" qualident ":" qualident "DO" StatementSequence "END" .
   76    ProcedureDeclaration  =  ProcedureHeading ";" ProcedureBody ident .
   77    ProcedureHeading =  "PROCEDURE" [ "*" ] identdef [ FormalParameters ] .
   78    ProcedureBody    =  DeclarationSequence [ "BEGIN" StatementSequence ] "END" .
   79    ForwardDeclaration  =  "PROCEDURE" "^" ident [ "*" ] [ FormalParameters ] .
   80    DeclarationSequence  =  {   "CONST" { ConstantDeclaration ";" }
   81                              | "TYPE"  { TypeDeclaration ";" }
   82                              | "VAR"   { VariableDeclaration ";" } }
   83                            {   ProcedureDeclaration ";"
   84                              | ForwardDeclaration ";" } .
   85    FormalParameters =  "(" [ FPSection { ";" FPSection } ] ")" [ ":" qualident ] .
   86    FPSection        =  [ "VAR" ] ident { "," ident } ":" FormalType .
   87    FormalType       =  { "ARRAY" "OF" } (qualident | ProcedureType) .
   88    ImportList       =  "IMPORT" import { "," import } ";" .
   89    import           =  ident [ ":=" ident ] .
   90    module           =  "MODULE" ident ";"
   91                        [ ImportList ] DeclarationSequence
   92                        [ "BEGIN" StatementSequence ] "END" ident "." .
   93  END Oberon.

    0 errors


Statistics:

  nr of terminals:        65 (limit   400)
  nr of non-terminals:    54 (limit   210)
  nr of pragmas:           0 (limit   435)
  nr of symbolnodes:     119 (limit   500)
  nr of graphnodes:      352 (limit  1500)
  nr of conditionsets:     4 (limit   100)
  nr of charactersets:     9 (limit   250)