%include {
#include <assert.h>
#include <stdlib.h>
#include "figure2-15-calc.h"
}

%syntax_error {
  printf("***SYNTAX ERROR at line %d!!! (trying recovery)\n",ParseState->linecount);
}

%parse_failure {
  printf("***PARSING FAILED!!!!\n");
  exit(99);
}

%parse_accept {
  /*  printf("SUCCESSFUL PARSE!!!\n"); */
}

%extra_argument { struct ParseState *ParseState }


%left PLUS.
%left MINUS.
%left DIVIDE.
%left MULTIPLY.
%nonassoc ASSIGN.



program ::= stmt_list.

stmt_list ::= stmt stmt_list.
stmt_list ::= .

stmt ::= ID ASSIGN expr.
stmt ::= READ ID.
stmt ::= WRITE expr.

expr ::= term term_tail.

term_tail ::= add_op term term_tail.
term_tail ::= .

term ::= factor factor_tail.

factor_tail ::= mult_op factor factor_tail.
factor_tail ::= .

factor ::= LPAREN expr RPAREN.
factor ::= ID.
factor ::= NUMBER.

add_op ::= PLUS.
add_op ::= MINUS.

mult_op ::= MULTIPLY.
mult_op ::= DIVIDE.