A parser for C99 declarations. Currently, the parser has the following limitations:

• Array sizes can only be *, n (where n is a positive integer), x (where x is a C identifier). In C99 they can be arbitrary expressions. See the ArrayType data type.
• _Bool, _Complex, and _Imaginary are not present.
• Untyped parameter lists (pre-K&R C) are not allowed.

The parser is incremental and generic (see CParser). Pretty and Arbitrary instances are provided for all the data types.

The entry point if you want to parse C declarations is parameter_declaration.

The parser above is derived from a modification of the YACC grammar for C99 found at http://www.quut.com/c/ANSI-C-grammar-y-1999.html, reproduced below.

%token IDENTIFIER TYPE_NAME INTEGER

%token TYPEDEF EXTERN STATIC AUTO REGISTER INLINE RESTRICT
%token CHAR SHORT INT LONG SIGNED UNSIGNED FLOAT DOUBLE CONST VOLATILE VOID
%token BOOL COMPLEX IMAGINARY
%token STRUCT UNION ENUM

%start parameter_list
%%

declaration_specifiers
	: storage_class_specifier
	| storage_class_specifier declaration_specifiers
	| type_specifier
	| type_specifier declaration_specifiers
	| type_qualifier
	| type_qualifier declaration_specifiers
	| function_specifier
	| function_specifier declaration_specifiers
	;

storage_class_specifier
	: TYPEDEF
	| EXTERN
	| STATIC
	| AUTO
	| REGISTER
	;

type_specifier
	: VOID
	| CHAR
	| SHORT
	| INT
	| LONG
	| FLOAT
	| DOUBLE
	| SIGNED
	| UNSIGNED
	| BOOL
	| COMPLEX
	| IMAGINARY
 	| STRUCT IDENTIFIER
	| UNION IDENTIFIER
	| ENUM IDENTIFIER
	| TYPE_NAME
	;

type_qualifier
	: CONST
	| RESTRICT
	| VOLATILE
	;

function_specifier
	: INLINE
	;

declarator
	: pointer direct_declarator
	| direct_declarator
	;

direct_declarator
	: IDENTIFIER
	| '(' declarator ')'
	| direct_declarator '[' type_qualifier_list ']'
	| direct_declarator '[' type_qualifier_list * ']'
	| direct_declarator '[' * ']'
 	| direct_declarator '[' IDENTIFIER ']'
	| direct_declarator '[' INTEGER ']'
	| direct_declarator '[' ']'
	| direct_declarator '(' parameter_list ')'
	| direct_declarator '(' ')'
	;

pointer
	: *
	| * type_qualifier_list
	| * pointer
	| * type_qualifier_list pointer
	;

type_qualifier_list
	: type_qualifier
	| type_qualifier_list type_qualifier
	;

parameter_list
	: parameter_declaration
	| parameter_list ',' parameter_declaration
	;

parameter_declaration
	: declaration_specifiers declarator
	| declaration_specifiers abstract_declarator
	| declaration_specifiers
	;

abstract_declarator
	: pointer
	| direct_abstract_declarator
	| pointer direct_abstract_declarator
	;

direct_abstract_declarator
	: '(' abstract_declarator ')'
	| '[' ']'
	| direct_abstract_declarator '[' ']'
	| '[' * ']'
	| direct_abstract_declarator '[' * ']'
	| '[' IDENTIFIER ']'
	| direct_abstract_declarator '[' IDENTIFIER ']'
	| '[' INTEGER ']'
	| direct_abstract_declarator '[' INTEGER ']'
	| '(' ')'
	| '(' parameter_list ')'
	| direct_abstract_declarator '(' ')'
	| direct_abstract_declarator '(' parameter_list ')'
	;

%%
#include <stdio.h>

extern char yytext[];
extern int column;

void yyerror(char const *s)
{
	fflush(stdout);
	printf("n%*sn%*sn", column, "^", column, s);
}