parser.y

%{
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#include "loc.h"
#include "ast.h"
#include "error.h"

#define YYLTYPE LocType

#define MAX_LINE_LENG      256
extern int line_no, col_no, opt_list;
extern char buffer[MAX_LINE_LENG];
extern FILE *yyin;        /* declared by lex */
extern char *yytext;      /* declared by lex */
extern int yyleng;

static Node root = NULL;

extern
#ifdef __cplusplus
"C"
#endif
int yylex(void);
static void yyerror(const char *msg);
extern int yylex_destroy(void);

%}

%locations

%token PROGRAM VAR ARRAY OF INTEGER REAL STRING FUNCTION PROCEDURE PBEGIN END IF THEN ELSE WHILE DO NOT AND OR

%token LPAREN RPAREN SEMICOLON DOT COMMA COLON LBRACE RBRACE DOTDOT ASSIGNMENT ADDOP SUBOP MULOP DIVOP LTOP GTOP EQOP GETOP LETOP NEQOP

%token IDENTIFIER REALNUMBER INTEGERNUM SCIENTIFIC LITERALSTR

%union {
  int val;
  char* text;
  double dval;
  Node node;
}

%type <Node> prog

%%

    /* define your snytax here */
    /* @n return the sturct LocType of "n-th node", ex: @1 return the PROGRAM node's locType
       $n return the $$ result you assigned to the rule, ex: $1 */
prog : PROGRAM {
        root = NULL;
        /*
        printf("program node is @ line: %d, column: %d\n",
                    @1.first_line, @1.first_column);
        yylval.val, yylval.text, yylval.dval to get the data (type defined in %union) you assigned by scanner.
        */
    }
    ;

%%

void yyerror(const char *msg) {
    fprintf(stderr,
            "[ERROR] line %4d:%3d %s, Unmatched token: %s\n",
            line_no, col_no-(int)yyleng+1, buffer, yytext);
}

int main(int argc, const char *argv[]) {

    if(argc > 2)
        fprintf( stderr, "Usage: ./parser [filename]\n" ), exit(0);

    FILE *fp = argc == 1 ? stdin : fopen(argv[1], "r");

    if(fp == NULL)
        fprintf( stderr, "Open file error\n" ), exit(-1);

    yyin = fp;
    yyparse();
    if(root){
        // do pass here
    }
    return 0;
}