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From: Terry Lambert <terry@lambert.org>
Message-Id: <199612060213.TAA21534@phaeton.artisoft.com>
Subject: Yacc -p<NAME> is broken
To: hackers@freebsd.org
Date: Thu, 5 Dec 1996 19:13:37 -0700 (MST)
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When you generate a y.tab.h file using yacc -p<NAME>... ie:


	yacc -v -p<NAME>

In the file y.tab.h, you get:


...
extern YYSTYPE <NAME>lval;


In reality, you should get:

...
#define	yylval <NAME>lval
extern YYSTYPE yylval;

This is because lex grammars frequently include y.tab.h:

%{
#include "y.tab.h"
#include <math.h>
#include <string.h>

...
%}

%%

...


and the value of yylval in the lexer is dependent on the value in the
yacc grammar -- which is dependent on the -p<NAME> parameter (in y.tab.c,
there is a:

#define yylval <NAME>lval


Frequently, if you are mixing grammars, you have a -P<NAME> on the lex
to go with the -p<NAME> on the yacc...


					Regards,
					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.