Replacements for the C preprocessor [closed]

Answer 1

Cog isn't exactly a pre-processor, but it does go in-line in the code and generates stuff on the fly.

Answer 2

If you're prepared to get your hands dirty with some C++, there's the Wave parser in Boost, which is built using the Spirit recursive descent parser. It's a complete C pre-processor that conforms to all the latest specs for C and C++ (and, by extension, Objective C, AFAICS).

It's highly modular so you can switch your own driver in that could do the extras you want.

http://www.boost.org/libs/wave/doc/introduction.html

Answer 3

I'd be interested to see what people come up with. I've tended to do small custom things with preprocessors written in Perl. It's easy to rig up a Makefile that calls the preprocessor. For example, here's a rule to call a program named 'meta' to generate 'file.c' from 'file.c.meta'.

% :: %.meta
    meta $< > $@

I'm doing fun things with 'meta' like generating custom fit C data structures. It's definitely a direction I'd suggest exploring. My hope is to eventually come up with a meta library roughly parallel to C++ templates.

Answer 4

Sure, the standard C preprocessor is very limited.
I've done such a tool recently: https://github.com/d-ash/perlpp

For example this

<?
    my @types = ('char', 'int', 'long'); 
    foreach (@types) {
?>
        <?= $_ ?> read_<?= uc($_) ?>(<?= $_ ?>* v);
<?  } ?>

becomes this

char read_CHAR(char* v);
int read_INT(int* v);
long read_LONG(long* v);

Syntax is similar to PHP, but it uses Perl instead, and can capture texts into Perl stings.

Edit by cxw — With @d-ash's approval, I am also a maintainer of perlpp. If you have questions, feel free to drop me a line!

Answer 5

You might want to consider m4.
http://www.gnu.org/software/m4/

Answer 6

I've thought about this same problem in the past. Make sure you are OK with the fact that anyone who wants to compile your code will need the new pre-processing tool as well. If you are the only one who will ever work on it, no problem, but if you want to make the code available to others, then you might want to consider whether or not adding a tool requirement is a good idea.