Re: C++, BISON, and M4

From:
red floyd <no.spam@here.dude>
Newsgroups:
comp.lang.c++
Date:
Wed, 03 Oct 2007 19:47:01 GMT
Message-ID:
<VkSMi.54849$Um6.47959@newssvr12.news.prodigy.net>
pendell@hotmail.com wrote:

Okay.

So I've just installed Fedora core 7 fresh from my machine. It comes
with G++, and bison installed directly.

So I try to make a program that uses bison. C++ chokes with the
error:

dimensions_dat.cc:1: error: expected constructor, destructor, or type
conversion before '(' token

Looking at the first line of dimensions_dat.cc, I find the following:

b4_copyright(Skeleton parser CASA Grammar Parsing with Bison,
             1984, 1989, 1990, 2000, 2001, 2002)

Commenting this line out, the error goes away.

So just comment it out and go merrily on my way, right? Nope! There
are several uses of macros very like this one, in very hard-to-reach
places in the code. Far better just to get the macros working in the
first place.

Macros -- right. Looking around, I found that these are m4 macros
(used with the m4 preprocessor) define in /usr/share/bison/c.m4 .

I think what is *supposed* to happen is that c++ is supposed to run
the m4 processor first before doing anything else. These macros are
replaced by standard code, which is then properly compiled.


No, g++ does not call m4. Check your makefile

Suggestions? Insight? If you don't know, where would I ask to find
out?


Suggestion: ask in a GNU newsgroup. Try gnu.g++.help

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