/*
 * This grammar sourced from:
 *   http://www.lysator.liu.se/c/ANSI-C-grammar-y.html
 */

%{

%}

%token IDENTIFIER CONSTANT STRING_LITERAL SIZEOF
%token PTR_OP INC_OP DEC_OP LEFT_OP RIGHT_OP LE_OP GE_OP EQ_OP NE_OP
%token BOOL_AND_OP BOOL_OR_OP MUL_ASSIGN DIV_ASSIGN MOD_ASSIGN ADD_ASSIGN
%token SUB_ASSIGN LEFT_ASSIGN RIGHT_ASSIGN AND_ASSIGN
%token XOR_ASSIGN OR_ASSIGN TYPE_NAME

%token LPAREN RPAREN LBRACKET RBRACKET LBRACE RBRACE
%token PERIOD COMMA COLON SEMICOLON QUESTIONMARK
%token PLUS MINUS STAR SLASH ASSIGN AND_OP OR_OP
%token BANG TILDE PERCENT CIRCUMFLEX
%token GT_OP LT_OP

%token TYPEDEF EXTERN STATIC AUTO REGISTER
%token CHAR SHORT INT LONG SIGNED UNSIGNED FLOAT DOUBLE CONST VOLATILE VOID
%token STRUCT UNION ENUM ELLIPSIS

%token CASE DEFAULT IF ELSE SWITCH WHILE DO FOR GOTO CONTINUE BREAK RETURN


%left COMMA
%right ASSIGN ADD_ASSIGN SUB_ASSIGN MUL_ASSIGN DIV_ASSIGN MOD_ASSIGN LEFT_ASSIGN RIGHT_ASSIGN AND_ASSIGN XOR_ASSIGN OR_ASSIGN
%right QUESTIONMARK COLON
%left BOOL_OR_OP
%left BOOL_AND_OP
%left OR_OP
%left CIRCUMFLEX
%left AND_OP
%left EQ_OP NE_OP
%left LT_OP GT_OP LE_OP GE_OP
%left LEFT_OP RIGHT_OP
%left PLUS MINUS
%left STAR SLASH PERCENT
%right NOT NEG
%right INC_OP SIZEOF DEC_OP
%left LBRACKET LPAREN PERIOD PTR_OP


%start translation_unit

%%

primary_expression
	: IDENTIFIER
	| CONSTANT
	| STRING_LITERAL
	| LPAREN expression RPAREN
	;

postfix_expression
	: primary_expression
	| postfix_expression LBRACKET expression RBRACKET
	| postfix_expression LPAREN RPAREN
	| postfix_expression LPAREN argument_expression_list RPAREN
	| postfix_expression PERIOD IDENTIFIER
	| postfix_expression PTR_OP IDENTIFIER
	| postfix_expression INC_OP
	| postfix_expression DEC_OP
	;

argument_expression_list
	: assignment_expression
	| argument_expression_list COMMA assignment_expression
	;

unary_expression
	: postfix_expression
	| INC_OP unary_expression
	| DEC_OP unary_expression
	| unary_operator cast_expression
	| SIZEOF unary_expression
	| SIZEOF LPAREN type_name RPAREN
	;

unary_operator
	: AND_OP
	| STAR
	| PLUS
	| MINUS
	| TILDE
	| BANG
	;

cast_expression
	: unary_expression
	| LPAREN type_name RPAREN cast_expression
	;

multiplicative_expression
	: cast_expression
	| multiplicative_expression STAR cast_expression
	| multiplicative_expression SLASH cast_expression
	| multiplicative_expression PERCENT cast_expression
	;

additive_expression
	: multiplicative_expression
	| additive_expression PLUS multiplicative_expression
	| additive_expression MINUS multiplicative_expression
	;

shift_expression
	: additive_expression
	| shift_expression LEFT_OP additive_expression
	| shift_expression RIGHT_OP additive_expression
	;

relational_expression
	: shift_expression
	| relational_expression LT_OP shift_expression
	| relational_expression GT_OP shift_expression
	| relational_expression LE_OP shift_expression
	| relational_expression GE_OP shift_expression
	;

equality_expression
	: relational_expression
	| equality_expression EQ_OP relational_expression
	| equality_expression NE_OP relational_expression
	;

and_expression
	: equality_expression
	| and_expression AND_OP equality_expression
	;

exclusive_or_expression
	: and_expression
	| exclusive_or_expression CIRCUMFLEX and_expression
	;

inclusive_or_expression
	: exclusive_or_expression
	| inclusive_or_expression OR_OP exclusive_or_expression
	;

logical_and_expression
	: inclusive_or_expression
	| logical_and_expression BOOL_AND_OP inclusive_or_expression
	;

logical_or_expression
	: logical_and_expression
	| logical_or_expression BOOL_OR_OP logical_and_expression
	;

conditional_expression
	: logical_or_expression
	| logical_or_expression QUESTIONMARK expression COLON conditional_expression
	;

assignment_expression
	: conditional_expression
	| unary_expression assignment_operator assignment_expression
	;

assignment_operator
	: ASSIGN
	| MUL_ASSIGN
	| DIV_ASSIGN
	| MOD_ASSIGN
	| ADD_ASSIGN
	| SUB_ASSIGN
	| LEFT_ASSIGN
	| RIGHT_ASSIGN
	| AND_ASSIGN
	| XOR_ASSIGN
	| OR_ASSIGN
	;

expression
	: assignment_expression
	| expression COMMA assignment_expression
	;

constant_expression
	: conditional_expression
	;

declaration
	: declaration_specifiers SEMICOLON
	| declaration_specifiers init_declarator_list SEMICOLON
	;

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

init_declarator_list
	: init_declarator
	| init_declarator_list COMMA init_declarator
	;

init_declarator
	: declarator
	| declarator ASSIGN initializer
	;

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

type_specifier
	: VOID
	| CHAR
	| SHORT
	| INT
	| LONG
	| FLOAT
	| DOUBLE
	| SIGNED
	| UNSIGNED
	| struct_or_union_specifier
	| enum_specifier
	| TYPE_NAME
	;

struct_or_union_specifier
	: struct_or_union IDENTIFIER LBRACE struct_declaration_list RBRACE
	| struct_or_union LBRACE struct_declaration_list RBRACE
	| struct_or_union IDENTIFIER
	;

struct_or_union
	: STRUCT
	| UNION
	;

struct_declaration_list
	: struct_declaration
	| struct_declaration_list struct_declaration
	;

struct_declaration
	: specifier_qualifier_list struct_declarator_list SEMICOLON
	;

specifier_qualifier_list
	: type_specifier specifier_qualifier_list
	| type_specifier
	| type_qualifier specifier_qualifier_list
	| type_qualifier
	;

struct_declarator_list
	: struct_declarator
	| struct_declarator_list COMMA struct_declarator
	;

struct_declarator
	: declarator
	| COLON constant_expression
	| declarator COLON constant_expression
	;

enum_specifier
	: ENUM LBRACE enumerator_list RBRACE
	| ENUM IDENTIFIER LBRACE enumerator_list RBRACE
	| ENUM IDENTIFIER
	;

enumerator_list
	: enumerator
	| enumerator_list COMMA enumerator
	;

enumerator
	: IDENTIFIER
	| IDENTIFIER ASSIGN constant_expression
	;

type_qualifier
	: CONST
	| VOLATILE
	;

declarator
	: pointer direct_declarator
	| direct_declarator
	;

direct_declarator
	: IDENTIFIER
	| LPAREN declarator RPAREN
	| direct_declarator LBRACKET constant_expression RBRACKET
	| direct_declarator LBRACKET RBRACKET
	| direct_declarator LPAREN parameter_type_list RPAREN
	| direct_declarator LPAREN identifier_list RPAREN
	| direct_declarator LPAREN RPAREN
	;

pointer
	: STAR
	| STAR type_qualifier_list
	| STAR pointer
	| STAR type_qualifier_list pointer
	;

type_qualifier_list
	: type_qualifier
	| type_qualifier_list type_qualifier
	;


parameter_type_list
	: parameter_list
	| parameter_list COMMA ELLIPSIS
	;

parameter_list
	: parameter_declaration
	| parameter_list COMMA parameter_declaration
	;

parameter_declaration
	: declaration_specifiers declarator
	| declaration_specifiers abstract_declarator
	| declaration_specifiers
	;

identifier_list
	: IDENTIFIER
	| identifier_list COMMA IDENTIFIER
	;

type_name
	: specifier_qualifier_list
	| specifier_qualifier_list abstract_declarator
	;

abstract_declarator
	: pointer
	| direct_abstract_declarator
	| pointer direct_abstract_declarator
	;

direct_abstract_declarator
	: LPAREN abstract_declarator RPAREN
	| LBRACKET RBRACKET
	| LBRACKET constant_expression RBRACKET
	| direct_abstract_declarator LBRACKET RBRACKET
	| direct_abstract_declarator LBRACKET constant_expression RBRACKET
	| LPAREN RPAREN
	| LPAREN parameter_type_list RPAREN
	| direct_abstract_declarator LPAREN RPAREN
	| direct_abstract_declarator LPAREN parameter_type_list RPAREN
	;

initializer
	: assignment_expression
	| LBRACE initializer_list RBRACE
	| LBRACE initializer_list COMMA RBRACE
	;

initializer_list
	: initializer
	| initializer_list COMMA initializer
	;

statement
	: labeled_statement
	| compound_statement
	| expression_statement
	| selection_statement
	| iteration_statement
	| jump_statement
	;

labeled_statement
	: IDENTIFIER COLON statement
	| CASE constant_expression COLON statement
	| DEFAULT COLON statement
	;

compound_statement
	: LBRACE RBRACE
	| LBRACE statement_list RBRACE
	| LBRACE declaration_list RBRACE
	| LBRACE declaration_list statement_list RBRACE
	;

declaration_list
	: declaration
	| declaration_list declaration
	;

statement_list
	: statement
	| statement_list statement
	;

expression_statement
	: SEMICOLON
	| expression SEMICOLON
	;

selection_statement
	: IF LPAREN expression RPAREN statement
	| IF LPAREN expression RPAREN statement ELSE statement
	| SWITCH LPAREN expression RPAREN statement
	;

iteration_statement
	: WHILE LPAREN expression RPAREN statement
	| DO statement WHILE LPAREN expression RPAREN SEMICOLON
	| FOR LPAREN expression_statement expression_statement RPAREN statement
	| FOR LPAREN expression_statement expression_statement expression RPAREN statement
	;

jump_statement
	: GOTO IDENTIFIER SEMICOLON
	| CONTINUE SEMICOLON
	| BREAK SEMICOLON
	| RETURN SEMICOLON
	| RETURN expression SEMICOLON
	;

translation_unit
	: external_declaration
	| translation_unit external_declaration
	;

external_declaration
	: function_definition
	| declaration
	;

function_definition
	: declaration_specifiers declarator declaration_list compound_statement
	| declaration_specifiers declarator compound_statement
	| declarator declaration_list compound_statement
	| declarator compound_statement
	;

%%
#include <stdio.h>

extern char yytext[];
extern int column;

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