www.pudn.com > 12cocorc.zip > C.ATG

COMPILER C 
 
/* An attempt to describe a subset of C */ 
 
CHARACTERS 
  letter   = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" . 
  digit    = "0123456789" . 
  hexdigit = digit + "ABCDEFabcdef" . 
  tab      = CHR(9) . 
  eol      = CHR(10) . 
  files    = letter + digit + ":\." . 
  chars    = CHR(32) .. CHR(255) - "'" . 
  strings  = CHR(32) .. CHR(255) - '"'. 
  macros   = ANY - eol . 
 
COMMENTS FROM "/*" TO "*/" 
 
IGNORE 
  tab + eol + CHR(13) 
 
TOKENS 
  identifier = ( "_" | letter) { "_" | letter | digit } . 
  number     = digit { digit } [ "." { digit }] [ "U" | "u" | "L" | "l" ] . 
  hexnumber  = "0" ( "x" | "X" ) hexdigit { hexdigit } [ "U" | "u" | "L" | "l" ] . 
  string     = '"' { strings } '"' . 
  char       = "'" [ "\" ] chars "'" . 
  library    = "<" files { files } ">" . 
 
PRAGMAS 
  PreProcessor = "#" {macros} . 
 
PRODUCTIONS 
 
  C                    = { Definition } EOF . 
 
/* Variable and Type Definitions */ 
 
  Definition           = [ StorageClass ] Type { "*" } identifier 
                            ( FunctionDefinition | VarList ";" ) . 
 
  StorageClass         = "auto" | "extern" | "register" | "static" . 
 
  Type                 =  "short" [ "int" ] 
                         | "long" [ "int" | "float" ] 
                         | "unsigned" [ "char" | "int" | "long" ] 
                         | "char" | "int" | "float" | "double" | "void" . 
 
  VarList              = ArraySize { "," { "*" } identifier ArraySize } . 
 
  ArraySize            = { "[" [ ConstExpression ] "]" } . 
 
/* Function Definitions */ 
 
  FunctionDefinition   = FunctionHeader ( ";" | FunctionBody ) . 
  FunctionHeader       = "(" [ FormalParamList ] ")" . 
  FunctionBody         = CompoundStatement . 
  FormalParamList      = FormalParameter { "," FormalParameter } . 
  FormalParameter      = Type { "*" } [ identifier ] ArraySize . 
 
/* Statements */ 
 
  Statement            = { Label } 
                         (  AssignmentExpression | BreakStatement 
                           | CompoundStatement | ContinueStatement 
                           | DoStatement | ForStatement 
                           | IfStatement  | NullStatement 
                           | ReturnStatement | SwitchStatement 
                           | WhileStatement ) . 
 
  Label                = "case" ConstExpression ":"  |  "default" ":" . 
 
/* There is no requirement that a switch statement be followed by a compound 
   statement.  Actually labels may be even more general */ 
 
  AssignmentExpression = Expression ";" . 
 
  BreakStatement       = "break" ";" . 
 
  CompoundStatement    = "{" { LocalDeclaration } { Statement } "}" . 
 
  ContinueStatement    = "continue" ";" . 
 
  DoStatement          = "do" Statement "while" "(" Expression ")" ";" . 
 
  ForStatement         = "for"  "(" [ Expression ] ";" [ Expression ] ";" [ Expression ] ")" Statement . 
 
  IfStatement          = "if" "(" Expression ")" Statement [ "else" Statement ] . 
 
  NullStatement        = ";" . 
 
  ReturnStatement      = "return" [ Expression ] ";" . 
                         /* Expression usually in parentheses */ 
 
  SwitchStatement      = "switch" "(" Expression ")" Statement . 
 
  WhileStatement       = "while" "(" Expression ")" Statement . 
 
/* LocalDeclarations */ 
 
  LocalDeclaration     = [ StorageClass ] Type { "*" } identifier 
                          ( FunctionHeader | VarList ) ";"  . 
 
/* Expressions, based on Kernighan and Ritchie: "The C Programming Language". 
   There does not seem to be a way to make this work in an LL(1) fashion, 
   but this generates a "working" parser */ 
 
  ConstExpression      = Expression . 
 
  Expression           = Conditional { AssignmentOperator Expression }. 
 
  Conditional          = LogORExp . 
 
  LogORExp             = LogANDExp   { "||" LogANDExp } . 
 
  LogANDExp            = InclORExp   { "&&" InclORExp }. 
 
  InclORExp            = ExclORExp   { "|" ExclORExp } . 
 
  ExclORExp            = ANDExp      { "^" ANDExp } . 
 
  ANDExp               = EqualExp    { "&" EqualExp } . 
 
  EqualExp             = RelationExp { ( "==" | "!=" ) RelationExp } . 
 
  RelationExp          = ShiftExp    { ( "<" | ">" | "<=" | ">=" ) ShiftExp }. 
 
  ShiftExp             = AddExp      { ( "<<" | ">>" ) AddExp } . 
 
  AddExp               = MultExp     { ( "+" | "-" ) MultExp } . 
 
  MultExp              = CastExp     { ( "*" | "/" | "%" ) CastExp } . 
 
  CastExp              = UnaryExp . 
 
/* we should really add 
                         | "(" identifier ")" CastExp . 
   but this breaks it badly */ 
 
  UnaryExp             = PostFixExp 
                         | ( "++" | "--" ) UnaryExp 
                         | UnaryOperator CastExp . 
 
/* we should really add 
                         | "sizeof" ( UnaryExp | "(" Type ")" ) . 
   but this breaks it badly */ 
 
  PostFixExp           = Primary 
                         { "[" Expression "]" 
                          | FunctionCall 
                          | "." identifier 
                          | "->" identifier 
                          | "++" 
                          | "--" 
                         } . 
 
  Primary              = identifier | string | char | number | "(" Expression ")" . 
 
  FunctionCall         = "(" [ ActualParameters ] ")" . 
 
  ActualParameters     = Expression { "," Expression } . 
 
  AssignmentOperator   =   "="  | "*=" | "/=" | "%=" | "+=" | "-=" | "&=" 
                         | "^=" | "|=" | "<<=" | ">>=" . 
 
  UnaryOperator        = "+" | "-" | "*" | "!" | "&" | "~" . 
 
END C.