Re: Newbie question - yyval problems

[Hans Aberg]

At 20:21 +0200 2002/05/19, Boris Köster wrote:
>I have a problem with bison, and I don´t know what I am doing
>wrong.
>%%
>
><INITIAL,paramscan>Tante|Geschlecht|Sexy  {
>                        yyval=strdup(yytext);

I figure it should be yylval here, and other similar places. Also define
YYSTYPE properly, say to char*.

As a matter of style, you seem to overuse the Flex start conditions; if you
put the parsing onto the Bison parser, it might be easier to generate
errors: from the parser instead of the lexer. For example:

Flex:

%{
#define get_text yylval(pos, red) \
  = strndup(yytext + (pos), yyleng - (pos + red))
  /* Starting at pos, taking away red from the end,
     I got strndup right -- I use C++! */
%}

%x string_scan

%%

"="               { get_text(0, 0); return ASSOP; }
{identifier}      { get_text(0, 0); return KEYWORD; }

\"                { BEGIN(string_scan); }
<string_scan>{string} { ... BEGIN(INITIAL); get_text(1, 1);
                        return STRING; }

...


Bison:

%%
...

ausdruck: KEYWORD ASSOP STRING EOL { ... };

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  Hans Aberg