<<Grammar Name="C_KernighanRitchie2"
encoding_class="ascii"
host_language="C#3.0"
reference="The C Programming Language, Kernighan&Ritchie, second edition"
comment="usage:input must be preprocessed source, remaining preprocessor directives are skipped by this grammar"
comment="showcases:demonstrates usage of parametrized peg rules and the case where correct parsing needs scoped "
comment="symbol table handling during parsing (in 'C' a typedef_name must be disambiguated from an "
comment="identifier by a lookup in the symbol tables (one for each block))"
>>
{
#region data members
int struct_level;
int par_list_level;
bool is_defined_type_spec;
bool is_in_typedef_definition;
string defined_typedef_name;
string declarator_ident;
System.Collections.Generic.List<System.Collections.Generic.HashSet<string>> typedefNames;
#endregion data members
#region semantic functions
bool typedef_name_lookup_()
{
if( is_defined_type_spec) return false;
else return isTypedefName(defined_typedef_name);
}
bool check_typedef_declarator_()
{
if( is_in_typedef_definition && par_list_level==0 && struct_level==0 ) insertTypedefName( declarator_ident );
return true;
}
bool enter_scope_() { pushScope(); return true; }
bool leave_scope_() { popScope(); return true; }
bool enter_params_(){++par_list_level;return true;}
bool leave_params_(){--par_list_level;return true;}
bool enter_struct_(){++struct_level;return true;}
bool leave_struct_(){--struct_level;return true;}
bool set_in_typedef_(){is_in_typedef_definition=true;return true;}
bool set_not_in_typedef_(){is_in_typedef_definition=false;return true;}
bool set_type_specifier_defined_() {is_defined_type_spec= true; return true;}
bool init_declaration_specifiers_(){is_defined_type_spec=false;return true;}
bool init_()
{
is_defined_type_spec=false;
is_in_typedef_definition= false;
par_list_level=0;
struct_level= 0;
typedefNames= null;
pushScope();
return true;
}
#endregion semantic functions
void insertTypedefName(string ident)
{
typedefNames[typedefNames.Count-1].Add(ident);
}
bool isTypedefName(string defined_typedef_name)
{
for(int i= typedefNames.Count;i>0;--i)
{
if( typedefNames[i-1].Contains(defined_typedef_name) ) return true;
}
return false;
}
void pushScope()
{
if( typedefNames==null ) typedefNames= new System.Collections.Generic.List<System.Collections.Generic.HashSet<string>>();
typedefNames.Add(new System.Collections.Generic.HashSet<string>());
}
void popScope()
{
if (typedefNames != null) typedefNames.RemoveAt(typedefNames.Count - 1);
}
}
//declarations
[1]^^translation_unit: init_ S @(external_declaration+) (!./FATAL<"illegal code before end of C file">);
[2]^external_declaration: function_definition / declaration ;
[3]^^function_definition:declaration_specifiers? declarator
declaration* compound_statement;
[4]^^declaration: set_not_in_typedef_ declaration_specifiers list<init_declarator,','>? @';' S;
[5]^^declaration_specifiers:
init_declaration_specifiers_
((storage_class_specifier /
type_specifier set_type_specifier_defined_ /
type_qualifier )S)+;
[6]^^storage_class_specifier:
('auto'/'register'/'static'/'extern') B / 'typedef' B set_in_typedef_;
[7]^^type_specifier: ^'void' B / ^'char' B / ^'short' B / ^'int' B / ^'long' B /
^'float' B / ^'double' B / ^'signed' B / ^'unsigned' B /
struct_or_union_specifier / enum_specifier / typedef_name ;
[8]^^type_qualifier: ('const'/'volatile') B;
[9]^^struct_or_union_specifier:
struct_or_union B S (identifier S member_block? / member_block);
[900]member_block: '{' enter_struct_ S @(struct_declaration+) leave_struct_ @'}' S;
[10]^^struct_or_union: 'struct' / 'union';
[11]^init_declarator: declarator ('=' S @initializer)?;
[12]^^struct_declaration:
specifier_qualifier_list list<struct_declarator,','> @';' S;
[13]^^specifier_qualifier_list:
(type_specifier S / type_qualifier S)+;
[14]^^struct_declarator: declarator (':' S @constant_expression )? /
':' S @constant_expression;
[15]^^enum_specifier: 'enum' B S (identifier S enum_block? / enum_block);
[150]enum_block: '{' S enumerator (',' S enumerator)* ','? S @'}' S;
[16]^^enumerator: identifier S ('=' S @constant_expression)?;
[17]^^declarator: pointer? direct_declarator;
[18]^^direct_declarator:(identifier:declarator_ident check_typedef_declarator_ S / '(' S @declarator @')' S)
(^'[' S constant_expression? @']' S/
'(' S parameter_type_list @')' S/
'(' S list<identifier,','>? @')' S
)*;
[19]^^pointer: ('*' S (type_qualifier S)* )+;
[20]^^parameter_type_list: enter_params_ (parameter_type_list_impl / leave_params_ !.) leave_params_;
[200]parameter_type_list_impl:
parameter_declaration S (',' S parameter_declaration S)* (',' S @'...' S)? ;
[21]^^parameter_declaration:
declaration_specifiers
(declarator/abstract_declarator?);
[22]^^initializer: assignment_expression /
'{' S initializer (',' S initializer)* ','? S @'}' S;
[23]^^type_name: specifier_qualifier_list abstract_declarator?;
[24]^^abstract_declarator:key_detail<pointer,direct_abstract_declarator>;
[25]^^direct_abstract_declarator:
key_detail<'(' S abstract_declarator @')',
(^'['S constant_expression? @']' S / '('S parameter_type_list? @')' S)+
>;
[26]^^typedef_name: identifier:defined_typedef_name typedef_name_lookup_ ;
//statements
[27]^statement: labeled_statement /
compound_statement /
selection_statement /
iteration_statement /
jump_statement /
expression_statement;
[28]^^labeled_statement:identifier S ':' S statement /
^'case' B S @constant_expression ':' S @statement/
^'default' S @':' S @statement ;
[29]^^expression_statement: expression @';' S / ';' S ;
[30]^^compound_statement:'{' enter_scope_ S declaration* statement* leave_scope_ @'}' S;
[31]^^selection_statement:^'if' S '(' S expression ')' S statement
(^'else' B S @statement)? /
^'switch' B S @'(' S @expression @')' S statement;
[32]^^jump_statement: ^'goto' B S @identifier S ';' S /
^'continue' S @';' S /
^'break' S @';' S /
^'return' B S expression? @';' S;
//expressions
[33]^expression: list<assignment_expression,','>;
[34]^assignment_expression:
!parenthized_type_name
unary_expression assignment_operator S @assignment_expression /
conditional_expression;
[35]^assignment_operator:'='!'=' / ('*=' / '/=' / '%=' / '+=' / '-=' / '<<=' /
'>>=' / '&=' / '^=' / '|=');
[36]^conditional_expression:
logical_or_expression
(^'?' S @expression @(^':') S @conditional_expression)?;
[37]^logical_or_expression:
binary<logical_and_expression,^'||'>;
[38]^logical_and_expression:
binary<inclusive_or_expression,^'&&'>;
[39]^inclusive_or_expression:
binary<exclusive_or_expression,^'|'>;
[40]^exclusive_or_expression:
binary<and_expression,^'^'>;
[41]^and_expression: binary<equality_expression,^'&'>;
[42]^equality_expression:binary<relational_expression,^('=='/'!=')>;
[43]^relational_expression:
binary<shift_expression,^('<='/'>='/'<'/'>')>;
[44]^shift_expression: binary<additive_expression,^('<<'/'>>')>;
[45]^additive_expression:binary<multiplicative_expression,^('+'/'-')>;
[46]^multiplicative_expression:
binary<cast_expression,^('*'/'/'/'%')>;
[47]^cast_expression: parenthized_type_name S @cast_expression / unary_expression ;
[470]parenthized_type_name:
'(' S type_name @')';
[48]^unary_expression: postfix_expression /
^'++' S @unary_expression /
^'--' S @unary_expression /
unary_operator S @cast_expression /
^'sizeof' S '(' S type_name S @')' S /
^'sizeof' B S @unary_expression;
[49]^unary_operator: '&'/'*'/'+'/'-'/'~'/'!';
[50]^postfix_expression:primary_expression
(
(^'[' S expression @']' /
call /
^'.' S @identifier /
^'->' S @identifier /
^'++' /
^'--'
) S
)*;
[500]^call: '(' S list<assignment_expression,','> @')' ;
[51]^primary_expression: (identifier /
constant /
string /
'(' S expression @')') S;
[52]constant: integer_constant /
character_constant /
floating_constant /
enumeration_constant;
[53]^identifier: !(keyword B) [A-Za-z_][A-Za-z_0-9]*;
[54]keyword: 'auto' / 'register' /'static' /'extern' /'typedef' /
'void' / 'char' / 'short' / 'int' / 'long' /
'float' / 'double' / 'signed' / 'unsigned'/
'const'/'volatile'/ 'struct' / 'union'/
'enum'/ 'case'/'default'/
'if'/'else'/ 'switch'/'goto'/
'continue'/'break'/'return'/
'sizeof'/ 'while' / 'do' / 'for';
[55]^iteration_statement:^'while' S @'(' S expression S @')' S @statement/
^'do' B S @statement @'while' S @'(' S expression @')' S @';' S/
^'for' S @'(' S for_init_expression? @';' S for_condition? @';' S for_incr? @')' S statement;
[550]^^for_init_expression:expression;
[551]^^for_condition: expression;
[552]^^for_incr: expression;
[56]S: (c_comment / c_preprocessing_directive / [ \r\n\v\t])*;
[57]c_comment: '/*' ( (!'*/' .)* '*/' / FATAL<"comment not closed before end of file"> );
[58]^constant_expression:conditional_expression;
[59]^string: l?["](escape_sequence/chars)*["];
[60]^integer_constant: (hexadecimal_constant / decimal_int)(l u/l u/ u l / u / l)? B ;
[61]^character_constant: l?['] (escape_sequence/char) ['];
[62]^floating_constant: (decimal_int exponent / decimal_int '.' fraction?)(l f/l f/ f l / f / l);
[63]^enumeration_constant:identifier;
[64]^exponent: [eE][+-]?[0-9]+;
[65]^escape_sequence: '\\' ([0-7]{1,3} / ['"?\\abfnrtv] / 'x' [0-9a-fA-F]+);
[66]^chars: [#x20#x21#x23-#x7F]+;
[67]^char: [#x20-#x26#x28-#x7F];
//generic rules
[70]list<operand,separator>:
binary<operand,separator>;
[80]binary<operand,operator>:
operand S (operator S @operand S)* ;
[100]key_detail<key,detail>:
key S detail? / detail;
[160]c_preprocessing_directive: '#' ('\\' '\r'?'\n' / !'\n' . )*;
[161]B: ![A-Za-z_0-9];
[162]^decimal_int: [0-9]+;
[163]^^fraction: decimal_int exponent? / exponent;
[164]^l: [lL];
[165]^u: [uU];
[166]^f: [fF];
[167]^hexadecimal_constant:('0x'/'0X')[0-9a-fA-F]+;
<</Grammar>>
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