Every time I run my parser, it will appear "syntax error in line 1 near <>" (Because there is a subroutine yyerror(char *s)). I think that's because there is something wrong with my rules in bison.
The file (c17.isc) I want to parse.
*c17 iscas example (to test conversion program only)
*---------------------------------------------------
*
*
* total number of lines in the netlist .............. 17
* simplistically reduced equivalent fault set size = 22
* lines from primary input gates ....... 5
* lines from primary output gates ....... 2
* lines from interior gate outputs ...... 4
* lines from ** 3 ** fanout stems ... 6
*
* avg_fanin = 2.00, max_fanin = 2
* avg_fanout = 2.00, max_fanout = 2
*
*
*
*
*
1 1gat inpt 1 0 >sa1
2 2gat inpt 1 0 >sa1
3 3gat inpt 2 0 >sa0 >sa1
8 8fan from 3gat >sa1
9 9fan from 3gat >sa1
6 6gat inpt 1 0 >sa1
7 7gat inpt 1 0 >sa1
10 10gat nand 1 2 >sa1
1 8
11 11gat nand 2 2 >sa0 >sa1
9 6
14 14fan from 11gat >sa1
15 15fan from 11gat >sa1
16 16gat nand 2 2 >sa0 >sa1
2 14
20 20fan from 16gat >sa1
21 21fan from 16gat >sa1
19 19gat nand 1 2 >sa1
15 7
22 22gat nand 0 2 >sa0 >sa1
10 20
23 23gat nand 0 2 >sa0 >sa1
21 19
My flex file is as follows and it is right. You can find some information about how my scanner work here. Error in the output of my flex file
declare.h
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
# define INPT 1
# define NOR 2
# define NAND 3
# define NOT 4
# define XOR 5
# define AND 6
# define BUFF 7
# define FROM 8
flex file is
%{
# include "declare.h"
# include "parse.tab.h"
/*gi=1,it's input;gi=8,it's fanout;otherwise,it's gate*/
static int gi=-1;
static int inum=0;
struct{
char *symbol;
int val;
} symtab[]={
{"inpt", INPT},
{"nor", NOR},
{"nand", NAND},
{"not", NOT},
{"xor", XOR},
{"and", AND},
{"buff", BUFF},
{"from",FROM},
{"0",0}
};
extern FILE *yyin;
extern int yylval;
%}
%start A B C D E
DIGITS [0-9]+
BLANK [ \t\n\r\f\v\b]+
ALPHA [a-z]+
%%
"*".*\n {BEGIN A; return(COMMENT);}
<A>{DIGITS} {yylval=atoi(yytext); BEGIN B; return(NUM);}
<B>{DIGITS}{ALPHA} {yylval=atoi(yytext); BEGIN C; return(GNAME);}
<C>{DIGITS} {yylval=atoi(yytext); BEGIN D; return(OPNUM);}
<C>{DIGITS}{ALPHA} {yylval=atoi(yytext); BEGIN A; return(FR);}
<D>{DIGITS} {inum=atoi(yytext);
yylval=inum;
if(gi==1)
{BEGIN A;}
if(gi!=1)
{BEGIN E;}
return(IPNUM);
}
<E>{DIGITS} {inum--;
yylval=atoi(yytext);
if(inum<0)
{BEGIN B; return(NUM);}
else
{BEGIN E; return(ILIST);}
}
{ALPHA} {yylval=lookup(yytext);
return(GTYPE);
}
">sa"[0-1] {yylval=atoi(&yytext[yyleng-1]);return(FAULT);}
{BLANK} ;
. ;
%%
int lookup(const char *s)
{
int i;
for (i = 0; symtab[i].val != 0; i++)
{
if (strcmp(symtab[i].symbol, s) == 0)
break;
}
return(symtab[i].val);
}
The right rules in bison file are as follows
parto:
| parto COMMENT
| parto parti
;
parti: NUM
{...}
GNAME
{...}
GTYPE
{...}
| parti partii
| parti partiii
;
partii:OPNUM
{...}
IPNUM
{...}
partiv
partv
;
partiii: FR
{...}
partiv
;
partiv:
| partiv FAULT
{...}
;
partv:
| partv ILIST
{...}
;
return
. The BEGIN operations have to be executed. They aren't being executed, so you're not switching into your start states. – Jonathan Leffler-DYYDEBUG
? You also need to turn the debug on:yydebug = 1;
in themain()
program. You're probably not getting the tokens you expect when you expect them. I've not tried compiling this code yet. Tracking the tokens is key (in my experience) to getting grammars to work. Otherwise, you're running blind. – Jonathan Lefflerbison -d grammar.y
generatesgrammar.tab.h
). You'll find that COMMENT is assigned the value 258, for example. Your scanner though is returning other numbers altogether because they're indeclare.h
. You'll have to fix this mismatch. One option is to#include "grammar.tab.h"
in your scanner; this is more or less normal. (People often include 'grammar.h' and only update 'grammar.h' if the content of grammar.tab.h changes, so you don't recompile the scanner all the time). – Jonathan Leffler