[Python-Dev] AST optimizer implemented in Python (original) (raw)

Meador Inge meadori at gmail.com
Sun Aug 12 23:05:15 CEST 2012

On Sat, Aug 11, 2012 at 1:30 PM, Victor Stinner <victor.stinner at gmail.com> wrote:

Hi,

I started to implement an AST optimizer in Python. It's easy to create a new AST tree, so I'm surprised that I didn't find any existing project. https://bitbucket.org/haypo/misc/src/tip/python/astoptimizer.py

Very cool.

To test its peephole optimizations (by checking manually its final bytecode), I wrote a patch for Python to disable Python internal peephole optimizer (on bytecode): https://bitbucket.org/haypo/misc/src/tip/python/compiledisablepeephole.patch

-- There is BytecodeAssembler [1], but it seems to be specialized on bytecode. There are (at least?) 3 different issues to implement an AST optimizer, but in C, not in Python: http://bugs.python.org/issue1346238 http://bugs.python.org/issue10399 http://bugs.python.org/issue11549

I read through the issues a while back and each is interesting in its own right. However, each is a specific implementation that is somewhat general, but geared towards one optimization (folding, inlining, etc...).

ISTM, that we need to step back a bit and define a what an AST optimizer for Python should look like (or even if it really makes any sense at all). I imagine having some facilities to manage and add new passes would be useful, for instance. I think this work probably merits a PEP (considering we essentially have four competing implementations for AST optimization now).

This is an interesting project and I would happily volunteer to help flesh out the details of a prototype and working on a PEP.

--

Meador

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