Okay Monks, I've done a few days of recon. Now I'm talking to Nick Clark and Ingy and Reini and others. Below is my latest e-mail to Nick about the whole thing, with some links interspersed for your convenience.

Now, on the count of 3, everybody tell me EXACTLY HOW I'M WRONG!

1 ... 2 ... 3!

<<< BEGIN E-MAIL >>>

Howdy Nick,

I'm probably misunderstanding some technical aspect of the whole RPython vs Perlito vs everything, here's my take, please correct me:

http://perlito.org/

Perlito is a language translation system AKA compiler, written in Perl 5. Perlito can parse a subset of Perl 5. Perlito can generate Javascript from the parsed subset of Perl 5. The generated Javascript can run in a fast Javascript VM like Google Chrome's V8. Since the V8 Javascript VM aims to eventually run as fast as native C, and it has the full backing of Google, then it may be a good final VM target to make a subset of Perl 5 run very fast.

http://tratt.net/laurie/tech_articles/articles/fast_enough_vms_in_fast_enough_time

RPython is a subset of the Python programming language, written in Python (I guess). RPython was created to create the PyPy Python JIT, which now runs faster than the original CPython interpreter VM. Any program written in RPython has the benefit of receiving an automatically-generated optimizing & tracing JIT compiler for free. Comparisons of the Converge language's VM written in C vs RPython show orders of magnitude speed increase by RPython's generated JIT. We would use the RPython language to implement a VM supporting (at least) a subset of Perl 5, which would give us the free Perl-specific JIT as a result, and again make a subset (or all) of Perl 5 run very fast.

http://cdent.org/

Ingy's C'Dent is a language translation system akin to Perlito, also able to parse a subset of Perl 5, which Ingy calls Perl5i. Instead of generating Javascript from Ingy's subset-of-Perl5, he aims to generate XS code, although I'm not sure how close he is to achieving that just yet. Since XS is pretty much C using native Perl data structs like SV etc, then in theory again we could end up with a subset of Perl 5 running very fast.

http://search.cpan.org/~mlehmann/Faster-0.1/

I think Marc Lehmann's Faster module on CPAN is similar to Ingy's goal of compiling some portion of your Perl 5 into XS. Faster may or may not be using Ingy's old Inline::C modules, which can also be used for some incremental runtime performance increase.

https://github.com/rurban/perl-compiler

Reini's work with the B compiler system seems to have made him enemies in the Pumpking and P5P camps, too bad. From what Reini tells me, he is mostly focused on making some fundamental changes to the Perl 5 language (unlikely to be adopted), and boosting startup speed by compiling to Perl Bytecode, etc. Reini is the only one working with ALL of Perl 5, not just a subset of Perl 5. I'm afraid that just-a-subset-of-Perl5 is a bad general route to take, because then you'll always be trying to catch up with the "real" Perl 5. So my thoughts are to try and have the full Perl B compiler system as the frontend so we are never just-a-subset, then we just need to decide which backend(s) to use to run the not-just-a-subset Perl 5 code in its native B form.

I think to somehow combine Perlito/Perl5i and RPython would amount to manually translating the Perlito/Perl5i subset-of-Perl parser from Perl (or whatever) to RPython; or manually translating RPython's JIT-creating system from Python to Perl. Both of these would work I think?

I think to somehow combine Reini's not-a-subset-of-Perl5 frontend with one or more of the Perlito/RPython/Perl5i backends would amount to some new Perl 5 code gluing them all together in the grand old Perl tradition of TMTOWTDI. We can run some performance tests on Perlito and Perl5i to see if we also need RPython. If we need RPython's awesome magical JIT (which I suspect we may), then we will have 3 new backends, and don't forget we still have the "real" Perl 5 interpreter VM to fall back on when we have code that isn't within any of the backends' subsets-of-Perl. So we create some Perl glue to make Reini's B system decide which of the 3 or 4 backends to run for each code segment based on some hard-coded rules derived from our performance tests on each backend's subset-of-Perl. The only thing the Perl users would know is that now when they run the /usr/bin/perl executable, it runs almost as fast as C.

Please do keep telling me exactly how wrong I am, you are clearly the most receptive and knowledgeable person I've got at this point. :)

Thanks!

~ Will

<<< END E-MAIL >>>

In reply to Perl 5 Optimizing Compiler, Part 2 by Will_the_Chill

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