accessing value passed from lexer in the parser file

Question

I have a simple config file as shown below

[main]
e_type=0x1b

In my lex file (test.l) when I encounter token e_type I call the following function and retunr T_E_TYPE token.

void tag ()  {
    yylval.str = malloc(strlen(yytext)+1);
    strcpy (yylval.str, yytext);
}

In the parser file (test.y) I have declared the union as follows.

%union {
   char *str;
   unsigned int n;
}

I am able to recognize [main] and e_type but If I try to print yylval.str from test.y file I get a segmentation fault.

How can I access the values I passed from lexer in the test.y file.

rici · Accepted Answer · 2015-08-05 01:57:08Z

0

The value of yylval corresponding to each token has been pushed onto the stack, and is available in the reduction rule as $n for some n (the symbols on the right hand side are numbered in order). You must declare the type-tag of each token so that bison knows which member of the union to use.

answered Aug 5, 2015 at 1:57

rici

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