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Re: On-topic: alternate Python implementations

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Paul Rubin, 04.08.2012 22:43:
> Stefan Behnel writes:
>>> Calling CPython hardly counts as compiling Python into C.
>> CPython is written in C, though. So anything that CPython does can be
>> done in C. It's not like the CPython project used a completely unusual
>> way of writing C code.
> 
> CPython is a relatively simple interpreter, and executing code 
> by invoking such an interpreter IMHO doesn't count as "compiling" it in
> any meaningful way.

Oh, CPython is substantially more than an interpreter. The eval loop is
only *one* way to use the runtime environment. Remember that it has many
builtin types and functions as well as a huge standard library. Much of the
runtime environment is already written in C or can be compiled down to C.
If you compile Python code into C code that avoids the eval loop and only
uses the CPython runtime environment (which is what Cython does), I think
that qualifies as compiling Python code to C. It's definitely the most
practical and user friendly way to do it.


>> You will always need some kind of runtime infrastructure when you
>> "compile Python into C", so you can just as well use CPython for that
>> instead of reimplementing it completely from scratch. 
> 
> Maybe there's parts of Cpython you can re-use, but having the CPython
> interpreter be the execution engine for "compiled" Python generators
> again fails the seriousness test of what it means to compile code.  If
> you mean something other than that, you might explain more clearly.

See above.


>> Both Cython and Nuitka do exactly that, 
> 
> I didn't know about Nuitka; it looks interesting but (at least after a
> few minutes looking) I don't have much sense of how it works.

It's mostly like Cython but without the type system, i.e. without all the
stuff that makes it useful in real life. Just a bare
Python-to-C++-in-CPython compiler, without much of a way to make it do what
you want.


>> Last I heard, PyPy had a couple of GCs to choose from,
> 
> PyPy doesn't compile to C

RPython (usually) does, though, and my guess is that the memory management
part of the runtime is written in RPython.


> but I guess compiling to C doesn't preclude
> precise GC, as long as the generated C code carefully tracks what C
> objects can contain GC-able pointers, and follows some constraints about
> when the GC can run.  Some other compilers do this so it's not as big a
> deal as it sounded like at first.  OK.

Yep, C really becomes a lot nicer when you generate it.


>> Huh? LuaJIT is a reimplementation of Lua that uses an optimising JIT
>> compiler specifically for Lua code. How is that similar to the Jython
>> runtime that runs *on top of* the JVM with its generic byte code based
>> JIT compiler?
> 
> I thought LuaJIT compiles the existing Lua VM code, but I haven't
> looked at it closely or used it.

Ok. It obviously reuses code, but the VM part of it is really different
from standard Lua.

Stefan

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On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-04 06:15 +0000
  Re: On-topic: alternate Python implementations Chris Angelico <rosuav@gmail.com> - 2012-08-04 16:34 +1000
    Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-04 10:54 +0000
      Re: On-topic: alternate Python implementations Stefan Krah <stefan-usenet@bytereef.org> - 2012-08-04 13:18 +0200
        Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 08:59 -0700
          Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 18:55 +0200
            Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 11:18 -0700
              Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 21:06 +0200
                Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 13:43 -0700
                Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 23:24 +0200
              Re: On-topic: alternate Python implementations MRAB <python@mrabarnett.plus.com> - 2012-08-04 20:24 +0100
          Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-05 00:54 +0000
            Re: On-topic: alternate Python implementations Paul Rubin <no.email@nospam.invalid> - 2012-08-04 18:38 -0700
              Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-05 02:19 +0000
                Re: On-topic: alternate Python implementations John Nagle <nagle@animats.com> - 2012-08-06 22:57 -0700
              Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-05 07:37 +0200
            Re: On-topic: alternate Python implementations Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-04 23:09 -0400
      Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 13:32 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 08:40 +0200
    Re: On-topic: alternate Python implementations Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-04 07:49 +0000
      Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 11:10 +0200
        Re: On-topic: alternate Python implementations Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-08-04 14:51 +0200
          Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 15:53 +0200
            Re: On-topic: alternate Python implementations Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2012-08-08 10:29 +0200
          Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 16:03 +0200
      Re: On-topic: alternate Python implementations Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-04 11:05 +0100
      Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-04 12:59 +0200
      Re: On-topic: alternate Python implementations Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-04 19:24 +0100
        Re: On-topic: alternate Python implementations Temia Eszteri <lamialily@cleverpun.com> - 2012-08-04 11:34 -0700
        Re: On-topic: alternate Python implementations Ben Finney <ben+python@benfinney.id.au> - 2012-08-06 01:21 +1000
      Re: On-topic: alternate Python implementations Zero Piraeus <schesis@gmail.com> - 2012-08-04 14:42 -0400
      Re: On-topic: alternate Python implementations Zero Piraeus <schesis@gmail.com> - 2012-08-04 14:56 -0400
      Re: On-topic: alternate Python implementations Ethan Furman <ethan@stoneleaf.us> - 2012-08-05 07:27 -0700
  Re: On-topic: alternate Python implementations Tim Roberts <timr@probo.com> - 2012-08-04 13:07 -0700
  Re: On-topic: alternate Python implementations jwp <james.pye@gmail.com> - 2012-08-04 15:05 -0700
  Re: On-topic: alternate Python implementations Jürgen A. Erhard <jae+python@jaerhard.com> - 2012-08-05 01:25 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-05 07:46 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-05 09:51 +0200
  Re: On-topic: alternate Python implementations Jürgen A. Erhard <jae+python@jaerhard.com> - 2012-08-05 14:28 +0200
  Re: On-topic: alternate Python implementations alex23 <wuwei23@gmail.com> - 2012-08-05 20:40 -0700
    Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-06 08:21 +0200
  Re: On-topic: alternate Python implementations Stefan Behnel <stefan_ml@behnel.de> - 2012-08-06 08:46 +0200
  Alternate Python extensions (was alternate Python implementations) rusi <rustompmody@gmail.com> - 2012-08-06 21:23 -0700
    Re: Alternate Python extensions (was alternate Python implementations) Stefan Behnel <stefan_ml@behnel.de> - 2012-08-07 07:09 +0200

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