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Almost finished with latest preprocessor.
Why am I always working on preprocessors tho? Shit...
Anyway, almost finished ok.
Idea is, basically, that inside a C source or header you can write a perl subroutine instead of `#define ...`.
The mechanism is rather simple:
```C (wat?)
macro mymacro($expr) {
· // perl code goes here
· return "$expr;"
};
```
`$expr` is just a string holding whatever block of code comes after an invocation of `mymacro`. You can use the builtins `tokenshift` and `tokenpop` on a string to get the first and last token, respectively, and then `tokensplit` gives you *all* the tokens.
Whatever string you return is what the expression you received is replaced by:
- You can just give back the expression as-is to get the exact same thing you wrote -- so `mymacro char* wat;` gives you `char* wat;`.
- But if you return a galaxy's worth of C code, then bam. Macro expanded into it, just like that. It's a perl subroutine, so let your imagination fly. Wanna run some scripts at (pre)compile time? Then you can.
- If you return an empty string, then puff. No code. Input consumed.
- If you give the name of another macro (eg "another_macro $expr;"), the expansion recurses.
- If you return the name of the currently executing macro, no recursion happens. This lets you wrap C keywords without (too much) fear.
It's kind of cool because a separate perl module is built from the macros themselves. So then you can include those in another C file. Syntax is basically more perl because why not:
```C (yes)
package mypkg;
· use lib "path/to/myshit/";
· use pm funk qw(mymacro);
```
The `lib` bit actually translates to `-I(path)` for gcc. But for some reason the way you add an include path in perl is `use lib "path"`, so yep. I get it's confusing but just go with the ::~ f l o w ~:: ok.
Then the `pm` stuff is not valid perl (i think), but I took the easy way out and invented it to ensure there is a way to say "OK I don't give a single shit about the C stuff, just give me these qw()'d funky macros from this file." If you simply `use funk qw(mymacro)` then you also get an `#include "funk.h"`.
Speaking of which, headers are automatically generated. Yeah, fuck you, I added `public` to C, bite me. It's actually quite sexy as I defined it using the preprocessor:
```C (yes but actually perl)
macro public($expr) {
· my $dst=cmamout()->{export};\
· tokentidy $expr;
· push @$dst,$expr;
· return "$expr;";
};
```
Where `cmamout()` is a hash from which the output is generated. Oh, and `tokentidy` is just a random builtin that cleans up extra whitespace, don't mind it.
So now the bad stuff: I have to fix a few things. For instance, notice how I had to escape a new line there? Yeah. It's called dumb fix to shit parsing, of course.
But overall I'm quite satisfied with this. And the reason why may not be so obvious so I'ma spill it out: backticks, motherfucker.
That's right. Have a source emitter written in an esoteric language?
```C (yes really but not really)
macro bashit($expr) {
· my ($exe,@args)=tokensplit $expr;
· return `$exe @args`;
};
```
So now you can fork off into parallel dimensions; what can I say pass the pipe brother.
MAMmoth in the room is yes, this depends on MAM. What is MAM? MAMMI. It's the original name of my infamous picture of an ouroboros eating it's own ass while stuck in limbo contemplating terrible life decisions of a build tool, avtomat (go ARSLASH <AR/> [habibi]).
So what's the deal with that? avtomat is a good build tool _for me_, not... ugh, you. I made it for *myself* baby things are not going to work out between us I'm sorry. MAM just does lots of things I wanted build tools to do in the __EXACT__ way I wanted them done. I'd say you should go use it too maybe, but actually don't and you shouldn't because I broke main some weeks ago to fix some other shit and then implement this. Yeah, pretty stupid, but what the hell. I'm the only user after all!
In conclusion, I am fully expecting to receive my mad props and street cred in the mail along with your marriage proposals en masse, effective immediately.
Further reading: https://youtube.com/watch/...5
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