[GRASS5] [bug #883] (grass) configure dosn't look for yacc

[Glynn Clements]

Markus Neteler wrote:

> > On the subject of lex/flex, configure.in currently has the following:
> > 
> > if test "$LEX" != "flex"; then
> >     AC_MSG_WARN([Consider installation of flex (replacement of lex).])
> > fi
> > 
> > Does anyone know the reason for this message?
> > 
> > If the .l files *need* flex, then this should be an error. OTOH, if
> > they work with lex, there doesn't seem much point in issuing a
> > warning.
> 
> the reason is that we had problems with "yylineno" in the past (if
> I recall properly). In:
> src/raster/r.binfer/binfer.l

OK; currently, the references to yylineno are commented out.

If the line number is required, it's probably better to include code
to track it, rather than have (f)lex do it for you.

> Flex provides something which is not always provided by lex.

AFAIK, AT&T lex does provide yylineno, but it is undocumented;
yylineno isn't part of the POSIX specification for lex.

Also, the flex manpage states that "%option yylineno" results in a
significant performance penalty (although control files aren't
generally large enough to be worth bothering about performance).

-- 
Glynn Clements <glynn.clements at virgin.net>