Macro system on B-Level?

I'm meditating about a macrosystem which is working after compilation and before execution

The idea is to flag subs as :macro and and to replace every call with the string the sub returns.

use B::MyMacro;
sub foo :macro {
  return "bar()"
}
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so that

 
print;
foo();
print;
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will be replaced with

print;
do { bar() };
print;
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Of course eval "string" needs also to be overridden, such that the macroreplacement will also be executed after eval's compilation.

This mechanism can already be realised using B::Deparse, RegEx and evals, but with rather fragile dependencies. I'm looking for a stable and simple opcode-based solution, replacing every macro-call with new opcodes.

IMHO, this approach would be much more stable and useful than codefilters, because "only perl can parse perl" š.

I'm wondering if nobody ever tried to implement this, googling and supersearching didn't bring any examples. Do you know any other similar approach?

Cheers Rolf

UPDATES:
(š) ... but "Even B:: can parse optree" : )

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Re: Macro system on B-Level? by moritz (Cardinal) on Nov 26, 2008 at 12:04 UTC
You could try to plug something like that with Devel::Declare, which for example Method::Signatures uses internally to introduce a new syntax. But be warned that it might be non-trivial.	[reply]
Re: Macro system on B-Level? by salva (Canon) on Nov 26, 2008 at 11:37 UTC
I'm wondering if nobody ever tried to implement this yes, I did, though I abandoned the idea because it got rather complex, and no other perl5-porters seemed to be interested on the idea :-( Search on the perl5-porters mailing list for the details: http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2006-05/msg00455.html. Probably, a more advanced version af the patch lays somewhere inside my hard disk.	[reply]
Re^2: Macro system on B-Level? by LanX (Saint) on Nov 26, 2008 at 12:05 UTC
(Ola\|Bom dia) salva! very, very interesting! 8 ) But as far as I understand, you want to hook into the compilation process. Right? I was thinking of modifying the optree after compilation, isn't it to complex during compilation? I think, one can already implement this using B::Generate ... but I'm just a beginner with opcodes, and have no overview about the implementation details Cheers Rolf	[reply]
Re: Macro system on B-Level? by jdporter (Paladin) on Nov 26, 2008 at 15:48 UTC
If all you're doing is saving function call overhead, it's not worth the trouble. If performance is that critical, drop down to XS or Inline::C or such like as. Between the mind which plans and the hands which build, there must be a mediator... and this mediator must be the heart.	[reply]
Re^2: Macro system on B-Level? by LanX (Saint) on Nov 26, 2008 at 15:57 UTC
No, no, no, your getting me wrong! It's not about function call overhead, it's about realising macros š, therefore helping to extend the syntax much better and reliable than codefilters ever can. perl 6 also intends to insert macro-support. But maybe you can show me a functional approach to solve this problem. : ) Cheers Rolf UPDATE: (š) to make it clearer, a macro is executed and operates on the parameters given before returning the new code to be inserted.	[reply]
Re^2: Macro system on B-Level? by LanX (Saint) on Nov 26, 2008 at 16:33 UTC
> If all you're doing is saving function call overhead I'd rather prefer using some kind of eval like `eval macro()` than doing XS. Coding in C just for linearising the code that's not worth the trouble. : ) Cheers Rolf	[reply] [d/l]