[pypy-dev] Parsing in PyPy (and runicode)

Frank Wierzbicki fwierzbicki at gmail.com
Fri Feb 27 19:38:39 CET 2009

On Fri, Feb 27, 2009 at 1:19 PM, Jacob Hallén <jacob at openend.se> wrote:
> Andrew Dalke, who is very thorough in his investigation of software, has
> written som interesting things about his experience with ANTLR as well as
> some other parsing projects. In short, he likes ANTLR as a tool, but in his
> application, it is considerably slower than some other alternatives.
> He also has something called python4ply, which is a ready, MIT licensed
> parser for Python.
> You can find his articles on
> http://www.dalkescientific.com/writings/diary/archive/
I see the part you are likely talking about:

It looks like every character read incurs several Python function
calls, which are a lot more expensive in Python than in Java or C++.
There's no easy change for this, so I'm pretty sure the
ANTLR-generated parser always going to be slower than PLY.

I wonder if producing a parser in C would work for PyPy if this is
unavoidable?  I know it misses the purpose of PyPy a bit -- just a
thought :)


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