I am trying to parse following lines:
BEGIN WRAP WIO3
NAME lgCell_prg160_io
CONDITION UNI_PLACE_GLOBAL && compBits
ENDS WIO3
The Grammar which I used to parse above lines are parsing till UNI_PLACE_GLOBAL then it gives parsing error.
Please help me to identify the mistake I have done.
I think it doesn't accept space so How can I allow to parse these lines??
I have done
lex.l
%{
#include <iostream>
#include <stdio.h>
const char s[2] = " ";
#include "yacca.tab.h"
char *token;
#define YY_DECL extern "C" int yylex()
int line_num = 1;
#ifdef DEBUG
#define RETURN(x) cerr << "\n--> found " << #x << "\n"; return x;
#else
#define RETURN(x) return x;
#endif
using namespace std;
%}
DOT "."
COLON ":"
SEMICOLON ";"
COMMA ","
ANGLE_LEFT "<"
ANGLE_RIGHT ">"
AT "@"
EQUAL "="
SQUARE_OPEN "["
SQUARE_CLOSE [^\\]"]"
OPENBRACE "\("
CLOSEBRACE "\)"
QUOTE "\""
QUOTE_OPEN "\""
QUOTE_CLOSE [^\\]"\""
SPACE " "
TAB "\t"
CRLF "\r\n"
QUOTED_PAIR "\\"[^\r\n]
DIGIT [0-9]
ALPHA [a-zA-Z]
QTEXT [0-9a-zA-Z!#$%&'()*+,\-.\/:;<=>?@\[\]^_`{|}~""]
/* [ \t] ; */
/* [ \s] ; */
%%
[ \t] ;
"//".* /* ignore comments */
NAME { yylval.sval = strdup(yytext);
return TOK_NAME; }
SIZE { yylval.sval = strdup(yytext);
return TOK_SIZE; }
ITERATE { yylval.sval = strdup(yytext);
return TOK_ITERATE; }
DIRECTION { yylval.sval = strdup(yytext);
return TOK_DIRECTION; }
STRAP { yylval.sval = strdup(yytext);
return TOK_STRAP; }
WRAP { yylval.sval = strdup(yytext);
return TOK_WRAP; }
VIA { yylval.sval = strdup(yytext);
return TOK_VIA; }
ENDS { yylval.sval = strdup(yytext);
return TOK_END; }
BEGIN { yylval.sval = strdup(yytext);
return TOK_BEGIN; }
BLOCK { yylval.sval = strdup(yytext);
return TOK_BLOCK; }
VERSION { yylval.sval = strdup(yytext);
return TOK_VERSION; }
STRUCTURE { yylval.sval = strdup(yytext);
return TOK_STRUCT; }
UNIQUE { yylval.sval = strdup(yytext);
return TOK_UNIQUE; }
REF { yylval.sval = strdup(yytext);
return TOK_REF; }
POSITION { yylval.sval = strdup(yytext);
return TOK_POS; }
CONDITION { yylval.sval = strdup(yytext);
return TOK_CON; }
ORIENTATION { yylval.sval = strdup(yytext);
return TOK_ORI; }
{QTEXT}* { yylval.sval = strdup(yytext);
return TOK_STRING; }
\\\n { printf("c> "); } /* ignore line continuation */
^{CRLF} { return TOK_EMPTY_LINE; }
{CRLF} {}
. {}/* ignore unknown chars */
\n { ++line_num; /*RETURN(ENDL); */ }
yacc.y
%{
#include <cstdio>
#include <cstring>
#include <iostream>
#include <stdio.h>
#define YYDEBUG 1
using namespace std;
extern "C" int yylex();
extern "C" FILE *yyin;
extern int line_num;
void yyerror(const char* s);
%}
// Symbols.
%union
{
char* sval;
};
%token <sval> TOK_NAME
%token <sval> TOK_SIZE
%token <sval> TOK_STRING
%token <sval> TOK_ITERATE
%token <sval> TOK_DIRECTION
%token <sval> TOK_STRAP
%token <sval> TOK_WRAP
%token <sval> TOK_VIA
%token <sval> TOK_EMPTY_LINE
%token <sval> TOK_BLOCK
%token <sval> TOK_LINE
%token <sval> TOK_BEGIN
%token <sval> TOK_END
%token <sval> TOK_VERSION
%token <sval> TOK_STRUCT
%token <sval> TOK_UNIQUE
%token <sval> TOK_REF
%token <sval> TOK_POS
%token <sval> TOK_CON
%token <sval> TOK_ORI
%token END ENDL
%%
language : program ;
program : block
| program block
;
block : TOK_BEGIN TOK_BLOCK TOK_STRING blockcontents TOK_END TOK_STRING
{
if (strcmp($3,$6) == 0 )
{
printf("\nHEADER %s ",$2);
printf("\nID %s ",$3);
}
else
{
printf("Block %s is not able to find its END\n" , $3);
}
}
| TOK_BEGIN TOK_BLOCK TOK_STRING blockcontents TOK_END { printf("Block %s is not able to find its END\n" , $3); }
| TOK_BEGIN TOK_STRING blockcontents TOK_END TOK_STRING {}
| TOK_BEGIN TOK_STRUCT TOK_STRING blockcontents TOK_END TOK_STRING
{
if (strcmp($3,$6) == 0 )
{
printf("\nHEADER %s ",$2);
printf("\nID %s \n",$3);
}
else
{
printf("Block %s is not able to find its END\n" , $3);
}
}
| TOK_BEGIN TOK_STRAP TOK_STRING blockcontents TOK_END TOK_STRING
{
if (strcmp($3,$6) == 0 )
{
printf("\nHEADER %s ",$2);
printf("\nID %s \n",$3);
}
else
{
printf("Block %s is not able to find its END\n" , $3);
}
}
| TOK_BEGIN TOK_WRAP TOK_STRING blockcontents TOK_END TOK_STRING
;
blockcontents : item
| blockcontents item
;
item : TOK_NAME TOK_STRING { cout << endl << $1 << "->" << $2 << " "; }
| TOK_SIZE TOK_STRING { cout << $1 << "->" << $2 << " "; }
| TOK_ITERATE TOK_STRING { cout << $1 << "->" << $2 << " "; }
| TOK_DIRECTION TOK_STRING { cout << endl << $1 << "->" << $2 << " " << endl; }
| TOK_STRAP TOK_STRING { cout << $1 << "->" << $2 << " "; }
| TOK_WRAP TOK_STRING { cout << $1 << "->" << $2 << " "; }
| TOK_VIA TOK_STRING { cout << $1 << "->" << $2 << " " << endl; }
| TOK_VERSION TOK_STRING {}
| TOK_UNIQUE TOK_STRING { cout << endl << $1 << "->" << $2 << " " << endl; }
| TOK_REF TOK_STRING { cout << endl << $1 << "->" << $2 << " " << endl; }
| TOK_POS TOK_STRING { cout << endl << $1 << "->" << $2 << " " << endl; }
| TOK_CON TOK_STRING { cout << endl << $1 << "->" << $2 << " " << endl; }
| TOK_ORI TOK_STRING { cout << endl << $1 << "->" << $2 << " " << endl; }
| block
;
%%
int main(void) {
FILE * pt = fopen("LG.txt", "r" );
if(!pt)
{
cout << "Bad Input.Noexistant file" << endl;
return -1;
}
yyin = pt;
do
{
//yydebug = 1;
yyparse();
}while (!feof(yyin));
}
void yyerror(const char *s) {
cout << "parse error on line " << line_num << "! Message: " << s << endl;
exit(-1);
}
extern "C" int yywrap()
{
return (1 == 1);
}
#include "lex.yy.c"
What you need to do it enable the debug mode of the lexer using the -d option flag and also enable the parse trace mode using the -t flag. You also have to add a couple of lines to the main program to enable the parser trace:
Add these lines to ayacc.y after the int main(void) {:
extern int yydebug;
yydebug = 1;
Now build with debug and trace:
flex -d lex.l
bison -t -d ayacc.y
Now when you run you get this:
Starting parse
Entering state 0
Reading a token: --(end of buffer or a NUL)
--accepting rule at line 80 ("BEGIN")
Next token is token TOK_BEGIN ()
Shifting token TOK_BEGIN ()
Entering state 1
Reading a token: --accepting rule at line 52 (" ")
--accepting rule at line 71 ("WRAP")
Next token is token TOK_WRAP ()
Shifting token TOK_WRAP ()
Entering state 7
Reading a token: --accepting rule at line 52 (" ")
--accepting rule at line 109 ("WIO3")
Next token is token TOK_STRING ()
Shifting token TOK_STRING ()
Entering state 29
Reading a token: --accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 119 ("
")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 56 ("NAME")
Next token is token TOK_NAME ()
Shifting token TOK_NAME ()
Entering state 12
Reading a token: --accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 109 ("lgCell_prg160_io")
Next token is token TOK_STRING ()
Shifting token TOK_STRING ()
Entering state 32
Reducing stack by rule 12 (line 109):
$1 = token TOK_NAME ()
$2 = token TOK_STRING ()
-> $$ = nterm item ()
Stack now 0 1 7 29
Entering state 27
Reducing stack by rule 10 (line 104):
$1 = nterm item ()
-> $$ = nterm blockcontents ()
Stack now 0 1 7 29
Entering state 48
Reading a token: --accepting rule at line 119 ("
")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 103 ("CONDITION")
Next token is token TOK_CON ()
Shifting token TOK_CON ()
Entering state 23
Reading a token: --accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 52 (" ")
--accepting rule at line 109 ("UNI_PLACE_GLOBAL")
Next token is token TOK_STRING ()
Shifting token TOK_STRING ()
Entering state 43
Reducing stack by rule 23 (line 120):
$1 = token TOK_CON ()
$2 = token TOK_STRING ()
NAME->lgCell_prg160_io
CONDITION->UNI_PLACE_GLOBAL
-> $$ = nterm item ()
Stack now 0 1 7 29 48
Entering state 46
Reducing stack by rule 11 (line 105):
$1 = nterm blockcontents ()
$2 = nterm item ()
-> $$ = nterm blockcontents ()
Stack now 0 1 7 29
Entering state 48
Reading a token: --accepting rule at line 52 (" ")
--accepting rule at line 109 ("&&")
Next token is token TOK_STRING ()
parse error on line 3! Message: syntax error
You can see that it is correctly ignoring the spaces using the lexer rule. Your problem is that the && symbol is being recognised as a TOK_STRING, which is not what is expected by the grammar rules.
Not knowing what the correct grammar for your language should be (you did not say) I cannot fix this for you without more information. You might want to fix the TOK_STRING rule to only match strings!