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|
/** ANSI C ANTLR v3 grammar
Translated from Jutta Degener's 1995 ANSI C yacc grammar by Terence Parr
July 2006. The lexical rules were taken from the Java grammar.
Jutta says: "In 1985, Jeff Lee published his Yacc grammar (which
is accompanied by a matching Lex specification) for the April 30, 1985 draft
version of the ANSI C standard. Tom Stockfisch reposted it to net.sources in
1987; that original, as mentioned in the answer to question 17.25 of the
comp.lang.c FAQ, can be ftp'ed from ftp.uu.net,
file usenet/net.sources/ansi.c.grammar.Z.
I intend to keep this version as close to the current C Standard grammar as
possible; please let me know if you discover discrepancies. Jutta Degener, 1995"
Generally speaking, you need symbol table info to parse C; typedefs
define types and then IDENTIFIERS are either types or plain IDs. I'm doing
the min necessary here tracking only type names. This is a good example
of the use of the global scope (called Symbols). Every rule that declares its usage
of Symbols pushes a new copy on the stack effectively creating a new
symbol scope. Also note rule declaration declares a rule scope that
lets any invoked rule see isTypedef boolean. It's much easier than
passing that info down as parameters. Very clean. Rule
direct_declarator can then easily determine whether the IDENTIFIER
should be declared as a type name.
I have only tested this on a single file, though it is 3500 lines.
This grammar requires ANTLR v3 (3.0b3 or higher)
Terence Parr
July 2006
ANTLR C# version - Kunle Odutola, November 2006
*/
grammar C;
options {
language=CSharp;
backtrack=true;
memoize=true;
k=2;
}
scope Symbols {
IDictionary types;
}
@header {
}
@members {
bool isTypeName(string name)
{
for (int i = Symbols_stack.Count-1; i>=0; i--)
{
Symbols_scope scope = (Symbols_scope)Symbols_stack[i];
if ( scope.types.Contains(name) )
{
return true;
}
}
return false;
}
bool isfinStruct(string token)
{
if (token.ToString() == "}")
{
return true;
}
return false;
}
}
translation_unit
scope Symbols; // entire file is a scope
@init {
$Symbols::types = new Hashtable();
}
: external_declaration+
;
/** Either a function definition or any other kind of C decl/def.
* The LL(*) analysis algorithm fails to deal with this due to
* recursion in the declarator rules. I'm putting in a
* manual predicate here so that we don't backtrack over
* the entire function. Further, you get a better error
* as errors within the function itself don't make it fail
* to predict that it's a function. Weird errors previously.
* Remember: the goal is to avoid backtrack like the plague
* because it makes debugging, actions, and errors harder.
*
* Note that k=1 results in a much smaller predictor for the
* fixed lookahead; k=2 made a few extra thousand lines. ;)
* I'll have to optimize that in the future.
*/
external_declaration
options {k=1;}
: ( declaration_specifiers? declarator declaration* '{' )=> function_definition
| declaration
;
function_definition
scope Symbols; // put parameters and locals into same scope for now
@init {
$Symbols::types = new Hashtable();
}
: declaration_specifiers? declarator
( declaration+ compound_statement // K&R style
| compound_statement // ANSI style
)
;
declaration
scope {
bool isTypedef;
}
@init {
$declaration::isTypedef = false;
}
: 'typedef' declaration_specifiers? {$declaration::isTypedef=true;}
init_declarator_list ';' // special case, looking for typedef
| declaration_specifiers init_declarator_list? ';'
;
declaration_specifiers
: ( storage_class_specifier
| type_specifier
| type_qualifier
)+
;
init_declarator_list
: init_declarator (',' init_declarator)*
;
init_declarator
: declarator ('=' initializer)?
;
storage_class_specifier
: 'extern'
| 'static'
| 'auto'
| 'register'
;
type_specifier
: 'void'
| 'char'
| 'short'
| 'int'
| 'long'
| 'float'
| 'double'
| 'signed'
| 'unsigned'
| struct_or_union_specifier
| enum_specifier
| type_id
;
type_id
: {isTypeName(input.LT(1).Text)}? IDENTIFIER
{Console.Out.WriteLine("\t" + input.LT(-1).Text + " " + input.LT(1).Text);}
;
struct_or_union_specifier
options {k=3;}
scope Symbols; // structs are scopes
@init {
$Symbols::types = new Hashtable();
}
: struct_or_union IDENTIFIER? '{' struct_declaration_list '}'
| struct_or_union IDENTIFIER
;
struct_or_union
: 'struct' {Console.Out.WriteLine("\r\nStruct\r\n{");}
| 'union' {Console.Out.WriteLine("\r\nUnion\r\n{");}
;
struct_declaration_list
: struct_declaration+
;
struct_declaration
: specifier_qualifier_list struct_declarator_list ';'
;
specifier_qualifier_list
: ( type_qualifier | type_specifier )+
;
struct_declarator_list
: struct_declarator (',' struct_declarator)*
;
struct_declarator
: declarator (':' constant_expression)?
| ':' constant_expression
;
enum_specifier
options {k=3;}
: 'enum' '{' enumerator_list '}'
| 'enum' IDENTIFIER '{' enumerator_list '}'
| 'enum' IDENTIFIER
;
enumerator_list
: enumerator (',' enumerator)*
;
enumerator
: IDENTIFIER ('=' constant_expression)?
;
type_qualifier
: 'const'
| 'volatile'
;
declarator
: pointer? direct_declarator
| pointer
;
direct_declarator
: ( IDENTIFIER
{
if ($declaration.Count>0 && $declaration::isTypedef) {
$Symbols::types[$IDENTIFIER.Text] = $IDENTIFIER.Text;
Console.Out.WriteLine("using " + input.LT(-1).Text + " = System." + input.LT(-2).Text + ";");
}
}
| '(' declarator ')'
)
declarator_suffix*
;
declarator_suffix
: '[' constant_expression ']'
| '[' ']'
| '(' parameter_type_list ')'
| '(' identifier_list ')'
| '(' ')'
;
pointer
: '*' type_qualifier+ pointer?
| '*' pointer
| '*'
;
parameter_type_list
: parameter_list (',' '...')?
;
parameter_list
: parameter_declaration (',' parameter_declaration)*
;
parameter_declaration
: declaration_specifiers (declarator|abstract_declarator)*
;
identifier_list
: IDENTIFIER (',' IDENTIFIER)*
;
type_name
: specifier_qualifier_list abstract_declarator?
;
abstract_declarator
: pointer direct_abstract_declarator?
| direct_abstract_declarator
;
direct_abstract_declarator
: ( '(' abstract_declarator ')' | abstract_declarator_suffix ) abstract_declarator_suffix*
;
abstract_declarator_suffix
: '[' ']'
| '[' constant_expression ']'
| '(' ')'
| '(' parameter_type_list ')'
;
initializer
: assignment_expression
| '{' initializer_list ','? '}'
;
initializer_list
: initializer (',' initializer)*
;
// E x p r e s s i o n s
argument_expression_list
: assignment_expression (',' assignment_expression)*
;
additive_expression
: (multiplicative_expression) ('+' multiplicative_expression | '-' multiplicative_expression)*
;
multiplicative_expression
: (cast_expression) ('*' cast_expression | '/' cast_expression | '%' cast_expression)*
;
cast_expression
: '(' type_name ')' cast_expression
| unary_expression
;
unary_expression
: postfix_expression
| '++' unary_expression
| '--' unary_expression
| unary_operator cast_expression
| 'sizeof' unary_expression
| 'sizeof' '(' type_name ')'
;
postfix_expression
: primary_expression
( '[' expression ']'
| '(' ')'
| '(' argument_expression_list ')'
| '.' IDENTIFIER
| '*' IDENTIFIER
| '->' IDENTIFIER
| '++'
| '--'
)*
;
unary_operator
: '&'
| '*'
| '+'
| '-'
| '~'
| '!'
;
primary_expression
: IDENTIFIER
| constant
| '(' expression ')'
;
constant
: HEX_LITERAL
| OCTAL_LITERAL
| DECIMAL_LITERAL
| CHARACTER_LITERAL
| STRING_LITERAL
| FLOATING_POINT_LITERAL
;
/////
expression
: assignment_expression (',' assignment_expression)*
;
constant_expression
: conditional_expression
;
assignment_expression
: lvalue assignment_operator assignment_expression
| conditional_expression
;
lvalue
: unary_expression
;
assignment_operator
: '='
| '*='
| '/='
| '%='
| '+='
| '-='
| '<<='
| '>>='
| '&='
| '^='
| '|='
;
conditional_expression
: logical_or_expression ('?' expression ':' conditional_expression)?
;
logical_or_expression
: logical_and_expression ('||' logical_and_expression)*
;
logical_and_expression
: inclusive_or_expression ('&&' inclusive_or_expression)*
;
inclusive_or_expression
: exclusive_or_expression ('|' exclusive_or_expression)*
;
exclusive_or_expression
: and_expression ('^' and_expression)*
;
and_expression
: equality_expression ('&' equality_expression)*
;
equality_expression
: relational_expression (('=='|'!=') relational_expression)*
;
relational_expression
: shift_expression (('<'|'>'|'<='|'>=') shift_expression)*
;
shift_expression
: additive_expression (('<<'|'>>') additive_expression)*
;
// S t a t e m e n t s
statement
: labeled_statement
| compound_statement
| expression_statement
| selection_statement
| iteration_statement
| jump_statement
;
labeled_statement
: IDENTIFIER ':' statement
| 'case' constant_expression ':' statement
| 'default' ':' statement
;
compound_statement
scope Symbols; // blocks have a scope of symbols
@init {
$Symbols::types = new Hashtable();
}
: '{' declaration* statement_list? '}'
;
statement_list
: statement+
;
expression_statement
: ';'
| expression ';'
;
selection_statement
: 'if' '(' expression ')' statement (options {k=1; backtrack=false;}:'else' statement)?
| 'switch' '(' expression ')' statement
;
iteration_statement
: 'while' '(' expression ')' statement
| 'do' statement 'while' '(' expression ')' ';'
| 'for' '(' expression_statement expression_statement expression? ')' statement
;
jump_statement
: 'goto' IDENTIFIER ';'
| 'continue' ';'
| 'break' ';'
| 'return' ';'
| 'return' expression ';'
;
IDENTIFIER
: LETTER (LETTER|'0'..'9')*
;
fragment
LETTER
: '$'
| 'A'..'Z'
| 'a'..'z'
| '_'
;
CHARACTER_LITERAL
: '\'' ( EscapeSequence | ~('\''|'\\') ) '\''
;
STRING_LITERAL
: '"' ( EscapeSequence | ~('\\'|'"') )* '"'
;
HEX_LITERAL : '0' ('x'|'X') HexDigit+ IntegerTypeSuffix? ;
DECIMAL_LITERAL : ('0' | '1'..'9' '0'..'9'*) IntegerTypeSuffix? ;
OCTAL_LITERAL : '0' ('0'..'7')+ IntegerTypeSuffix? ;
fragment
HexDigit : ('0'..'9'|'a'..'f'|'A'..'F') ;
fragment
IntegerTypeSuffix
: ('u'|'U')? ('l'|'L')
| ('u'|'U') ('l'|'L')?
;
FLOATING_POINT_LITERAL
: ('0'..'9')+ '.' ('0'..'9')* Exponent? FloatTypeSuffix?
| '.' ('0'..'9')+ Exponent? FloatTypeSuffix?
| ('0'..'9')+ Exponent FloatTypeSuffix?
| ('0'..'9')+ Exponent? FloatTypeSuffix
;
fragment
Exponent : ('e'|'E') ('+'|'-')? ('0'..'9')+ ;
fragment
FloatTypeSuffix : ('f'|'F'|'d'|'D') ;
fragment
EscapeSequence
: '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\')
| OctalEscape
;
fragment
OctalEscape
: '\\' ('0'..'3') ('0'..'7') ('0'..'7')
| '\\' ('0'..'7') ('0'..'7')
| '\\' ('0'..'7')
;
fragment
UnicodeEscape
: '\\' 'u' HexDigit HexDigit HexDigit HexDigit
;
WS : (' '|'\r'|'\t'|'\u000C'|'\n') {$channel=HIDDEN;}
;
COMMENT
: '/*' ( options {greedy=false;} : . )* '*/' {$channel=HIDDEN;}
;
LINE_COMMENT
: '//' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
;
// ignore #line info for now
LINE_COMMAND
: '#' ~('\n'|'\r')* '\r'? '\n' {$channel=HIDDEN;}
; |
[ANTLR] : quelques questions.
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