Wirth-AT-grammars/P4/p4_pascal.lst

Coco/R - Compiler-Compiler V1.53
Released by Pat Terry 17 September 2002
Source file: pascal_impl/p4_pascal.atg

Listing:

    1  (* Pascal P4 ATG for Coco/R *)
    2  (* Pascal-4 (1977) - N. Wirth's fourth Pascal implementation *)
    3  (* Features: Nested procedures/functions, empty procedures *)
    4  
    5  (* Tags: P4, PASCAL4, WIRTH *)
    6  
    7  COMPILER PascalP4
    8  
    9  CHARACTERS
   10    eol = CHR(13) .
   11    letter = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" .
   12    digit = "0123456789" .
   13  IGNORE CHR(9) .. CHR(13)
   14  COMMENTS FROM "(*" TO "*)" NESTED
   15  
   16  TOKENS
   17    ident = letter { letter | digit } .
   18  
   19  PRODUCTIONS
   20  
   21    Program = "program" ident ";" Block "." .
   22  
   23    Block = [ UnitSection ] DeclPart Statements .
   24  
   25    UnitSection = "unit" ident ";" { FileSection } "end" ident "." .
   26  
   27    FileSection = ident { ";" ident } .
   28  
   29    DeclPart = [ ConstSection ] [ TypeSection ] [ VarSection ] [ ProcDecl ].
   30  
   31    ConstSection = "const" ConstDeclList { ";" ConstDeclList } .
   32  
   33    ConstDeclList = ident "=" Value { ";" ident "=" Value } .
   34  
   35    TypeSection = "type" TypeDeclList { ";" TypeDeclList } .
   36  
   37    TypeDeclList = ident "=" Type { ";" ident "=" Type } .
   38  
   39    VarSection = "var" VarDeclList { ";" VarDeclList } .
   40  
   41    VarDeclList = identlist ":" Type .
   42  
   43    identlist = ident { "," ident } .
   44  
   45    Type = SimpleType | StructType | PointerType | ArrayType | SetType | ProcType .
   46  
   47    SimpleType = integertype | realtype | charType | booleanType .
   48  
   49    integertype = "integer" .
   50    realtype = "real" .
   51    charType = "char" .
   52    booleanType = "boolean" .
   53  
   54    StructType = ArrayType | RecordType | SetType | ProcType .
   55  
   56    ArrayType = "array" "[" IndexList "]" "of" Type .
   57  
   58    IndexList = SimpleType { "," SimpleType } .
   59  
   60    RecordType = "record" FieldList "end" .
   61  
   62    FieldList = Field { ";" Field } .
   63  
   64    Field = identlist ":" Type .
   65  
   66    SetType = "set" "of" Type .
   67  
   68    ProcType = "procedure" ParList ";" { [ ConstDecl ; TypeDecl ; VarDecl ; ProcDecl ] } ";" .
*****                                                     ^ invalid Factor
*****                                                                ^ invalid Factor
*****                                                                          ^ invalid Factor
   69  
   70    Statements = Statement { ";" Statement } .
   71  
   72    Statement = IfStatement
   73             | CaseStatement
   74             | WhileStatement
   75             | RepeatStatement
   76             | ForStatement
   77             | Assignment
   78             | ProcCall
   79             | ReturnStatement
   80             | EmptyStatement
   81             | ProcDecl ;   (* Nested procedure *)
*****                        ^ invalid Factor
   82  
   83    IfStatement = "if" Expr "then" Stmts { "else" Stmts } .
*****                ^ invalid Factor
   84  
   85    CaseStmt = "case" Expr of { CaseItem ";" } "end" .
   86  
   87    CaseItem = LabelList ":" Stmts .
   88  
   89    LabelList = Label { "," Label } .
   90  
   91    Label = number .
   92  
   93    WhileStmt = "while" Expr "do" Stmts .
   94  
   95    RepeatStmt = "repeat" Stmts "until" Expr .
   96  
   97    ForStmt = "for" ident ":=" Expr "to" Expr "do" Stmts
   98             | "for" ident ":=" Expr "downto" Expr "do" Stmts .
   99  
  100    Assignment = Var ":=" Expr .
  101  
  102    ProcCall = ident "(" [ ParamList ] ")" .
  103  
  104    ParamList = Param { "," Param } .
  105  
  106    Param = Expr .
  107  
  108    ReturnStmt = "return" [ Expr ] .
  109  
  110    EmptyStatement = "" .
  111  
  112    Expr = SimpleExpr [ Relationship SimpleExpr ] .
  113  
  114    Relationship = "=" | "#" | "<" | ">" | "<=" | ">=" | "<>" .
  115  
  116    SimpleExpr = ["+" | "-"] Term { ("+" | "-") Term } .
  117  
  118    Term = Factor { ("*" | "/" | "div" | "mod" | "&") Factor } .
  119  
  120    Factor = ["+" | "-"] ["not"] Primary .
  121  
  122    Primary = number | ident | string | "(" Expr ")" | Primary "^" .
  123  
  124    number = digit { digit } .
  125  
  126    ident = letter { letter | digit } .
  127  
  128    string = "'" { noQuote1 | "''" } "'" .
  129  
  130    EndProgram = "." .
  131  EOF

    5 errors