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%{
#include <stdio.h>
#include "ast.h"
extern char *yytext;
extern int yylineno;
extern int yylex();
ASTNode *ast_root;
void yyerror(const char *s) {
fprintf(stderr, "Parse error at token \"%s\", line %d: %s\n", yytext, yylineno, s);
}
%}
%union {
int num;
char *id;
int op;
struct ASTNode *node;
}
%start program
%token <id> TOKEN_IDENTIFIER
%token <num> TOKEN_NUMERAL
%token TOKEN_ASSIGN
%token TOKEN_LEFT_PARENTHESIS TOKEN_RIGHT_PARENTHESIS
%token TOKEN_SEMICOLON
%token TOKEN_SKIP
%token TOKEN_IF TOKEN_THEN TOKEN_ELSE TOKEN_END TOKEN_WHILE TOKEN_DO
%token TOKEN_PLUS TOKEN_MINUS TOKEN_MULTIPLY
%token TOKEN_NOT TOKEN_OR TOKEN_AND
%token TOKEN_EQUALS TOKEN_NOT_EQUALS TOKEN_LESS_THAN TOKEN_LESS_EQUAL TOKEN_GREATER_THAN TOKEN_GREATER_EQUAL
%type <node> program statement variable arithmetic_expression boolean_expression
%type <op> arithmetic_operation boolean_operation relational_operation
%%
program : statement
{ ast_root = $1; }
;
statement : TOKEN_SKIP
{ $$ = ast_skip(); }
| variable TOKEN_ASSIGN arithmetic_expression
{ $$ = ast_assign($1, $3); }
| TOKEN_LEFT_PARENTHESIS statement TOKEN_SEMICOLON statement TOKEN_RIGHT_PARENTHESIS
{ $$ = ast_seq($2, $4); }
| TOKEN_IF boolean_expression TOKEN_THEN statement TOKEN_ELSE statement TOKEN_END
{ $$ = ast_if($2, $4, $6); }
| TOKEN_WHILE boolean_expression TOKEN_DO statement TOKEN_END
{ $$ = ast_while($2, $4); }
;
variable : TOKEN_IDENTIFIER
{ $$ = ast_var($1); }
;
arithmetic_expression : TOKEN_LEFT_PARENTHESIS arithmetic_expression arithmetic_operation arithmetic_expression TOKEN_RIGHT_PARENTHESIS
{ $$ = ast_aop($3, $2, $4); }
| variable
{ $$ = $1; }
| TOKEN_NUMERAL
{ $$ = ast_int($1); }
;
arithmetic_operation : TOKEN_PLUS
{ $$ = AOP_ADD; }
| TOKEN_MINUS
{ $$ = AOP_SUB; }
| TOKEN_MULTIPLY
{ $$ = AOP_MUL; }
;
boolean_expression : TOKEN_LEFT_PARENTHESIS boolean_expression boolean_operation boolean_expression TOKEN_RIGHT_PARENTHESIS
{ $$ = ast_bop($3, $2, $4); }
| TOKEN_NOT boolean_expression
{ $$ = ast_not($2); }
| arithmetic_expression relational_operation arithmetic_expression
{ $$ = ast_rop($2, $1, $3); }
;
boolean_operation : TOKEN_OR
{ $$ = BOP_OR; }
| TOKEN_AND
{ $$ = BOP_AND; }
;
relational_operation : TOKEN_EQUALS
{ $$ = ROP_EQ; }
| TOKEN_NOT_EQUALS
{ $$ = ROP_NE; }
| TOKEN_LESS_THAN
{ $$ = ROP_LT; }
| TOKEN_LESS_EQUAL
{ $$ = ROP_LE; }
| TOKEN_GREATER_THAN
{ $$ = ROP_GT; }
| TOKEN_GREATER_EQUAL
{ $$ = ROP_GE; }
;
%%
|
