Compiler C or Python?

**John Roth** · Jul 18 '05, 02:12 AM

Re: Compiler C or Python?

"Jørgen Hermanrud Fjeld" <jhf@hex.no> wrote in message
news:mailman.10 62498963.22409. python-list@python.org ...
On Tue, Aug 26, 2003 at 04:33:17PM -0500, Jeff Epler wrote:[color=blue]
> 4. It's possible to write code so that __import__ uses compiler.compil e
> instead of the written-in-C compiler, but I don't have this code handy.
> Also, a test suite is needed, and presumably a written-in-C implementation
> as well. (option 2: make the compiler.compil e interface the standard
> compiler, and let the builtin compiler support a Python subset
> sufficient to bootstrap the written-in-python compiler, or arrange
> to ship .pyc of the compiler package and completely get rid of the
> written-in-C compiler)[/color]

Could you make an effort to locate that code, or give some suggestions to
where I might locate it myself?

And in general, if should want to alter the Python compiler, should I start
with the Python or C version?
As far as I can see from your email the Python version is easier to modify,
but why two compilers? Isn't that a lot to maintain?

[John Roth]
I believe that the Python version of the compiler uses the C version
in several places. The documentation mentions the parser and the
creation of the concrete syntax tree.

In other words, it's not a complete implementation. It also seems
to have some problems with error checking. The primary use seems
to be manifesting an abstract syntax tree for program analysis tools
to work on.

John Roth

Sincerely
Jørgen

**Michael Hudson** · Jul 18 '05, 02:12 AM

Re: Compiler C or Python?

jhf@hex.no (Jørgen Hermanrud Fjeld) writes:
[color=blue]
> On Tue, Aug 26, 2003 at 04:33:17PM -0500, Jeff Epler wrote:[color=green]
> > 4. It's possible to write code so that __import__ uses compiler.compil e
> > instead of the written-in-C compiler, but I don't have this code handy.
> > Also, a test suite is needed, and presumably a written-in-C implementation
> > as well. (option 2: make the compiler.compil e interface the standard
> > compiler, and let the builtin compiler support a Python subset
> > sufficient to bootstrap the written-in-python compiler, or arrange
> > to ship .pyc of the compiler package and completely get rid of the
> > written-in-C compiler)[/color]
>
> Could you make an effort to locate that code, or give some suggestions to
> where I might locate it myself?
>
> And in general, if should want to alter the Python compiler, should
> I start with the Python or C version?[/color]

Whichever's easiest :-) This is usually the Python one.

A toy that might come in handy is an interactive mode (based on
code.Interactiv eConsole) that compiles input with the customized
compiler.
[color=blue]
> As far as I can see from your email the Python version is easier to
> modify, but why two compilers? Isn't that a lot to maintain?[/color]

The Lib/compiler/ package is pretty slow. Also, making that the only
compiler might lead to irritating bootstrapping problems (which I now
see Jeff talked about...).

Cheers,
mwh

--
Do I do everything in C++ and teach a course in advanced swearing?
-- David Beazley at IPC8, on choosing a language for teaching

**Jørgen Hermanrud Fjeld** · Jul 18 '05, 02:13 AM

Re: Compiler C or Python?

On Tue, Sep 02, 2003 at 11:37:03AM +0000, Michael Hudson wrote:[color=blue]
> jhf@hex.no (Jørgen Hermanrud Fjeld) writes:[color=green]
> > And in general, if should want to alter the Python compiler, should
> > I start with the Python or C version?[/color]
>
> Whichever's easiest :-) This is usually the Python one.
>[/color]
Then I shall start with that one. Are there any other arguments/reasons to
choose one or the other? That is technicalities one should consider.
[color=blue]
> A toy that might come in handy is an interactive mode (based on
> code.Interactiv eConsole) that compiles input with the customized
> compiler.[/color]
Thanks, this can make the task at hand a lot easier.
[color=blue][color=green]
> > As far as I can see from your email the Python version is easier to
> > modify, but why two compilers? Isn't that a lot to maintain?[/color]
>
> The Lib/compiler/ package is pretty slow. Also, making that the only
> compiler might lead to irritating bootstrapping problems (which I now
> see Jeff talked about...).[/color]
Yes, but the code it generates will be fast enough for my purposes.
Do you happen to know how consistency between the compilers is maintained?

Sincerely
Jørgen

**Michael Hudson** · Jul 18 '05, 02:13 AM

Re: Compiler C or Python?

jhf@hex.no (Jørgen Hermanrud Fjeld) writes:
[color=blue]
> On Tue, Sep 02, 2003 at 11:37:03AM +0000, Michael Hudson wrote:[color=green]
> > jhf@hex.no (Jørgen Hermanrud Fjeld) writes:[color=darkred]
> > > And in general, if should want to alter the Python compiler, should
> > > I start with the Python or C version?[/color]
> >
> > Whichever's easiest :-) This is usually the Python one.
> >[/color]
> Then I shall start with that one. Are there any other arguments/reasons to
> choose one or the other? That is technicalities one should consider.[/color]

I don't think so. The code they produce is essentially identical,
AFAIK (the only difference I'm aware of is the ordering of the
constants in co_consts -- hardly critical).

Oh, Raymond Hettinger added some bytecode rewriting steps to the C
compiler in 2.3. I don't think Lib/compiler does these.

For *very* simple tweaks I sometimes find Python/compile.c easier to
work with, but that's probably because Python/compile.c is a hunk of
procedural C code I've worked with a fair bit and Lib/compiler is an
OOP-y framework-y hunk of code I don't quite understand. Someone
starting from scratch is unlikely to find this.

Obviously, Python/compile.c gets more testing, and probably has fewer
bugs.
[color=blue][color=green][color=darkred]
> > > As far as I can see from your email the Python version is easier to
> > > modify, but why two compilers? Isn't that a lot to maintain?[/color]
> >
> > The Lib/compiler/ package is pretty slow. Also, making that the only
> > compiler might lead to irritating bootstrapping problems (which I now
> > see Jeff talked about...).[/color]
> Yes, but the code it generates will be fast enough for my purposes.[/color]

Oh yes, the compiled code runs at the same speed.
[color=blue]
> Do you happen to know how consistency between the compilers is
> maintained?[/color]

Blood and toil :-/

Cheers,
mwh

--
I have long since given up dealing with people who hold idiotic
opinions as if they had arrived at them through thinking about
them. -- Erik Naggum, comp.lang.lisp

Compiler C or Python?

Compiler C or Python?

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