Ann: Plex 0.1 - A Lexical Analysis Module

Neel Krishnaswami neelk at
Thu Feb 10 03:10:10 CET 2000

Greg Ewing <greg at> wrote:
> Having spent a couple of years wondering "when is someone
> going to write a decent lexing module for Python", I finally
> decided to do it myself.

Very slick, especially the the constructor-style you use with the
FSMs. A first look at the code suggests that unlike with regexps, you
could build symbolic lexers for /arbitrary sequences of Python

This is cool all by itself -- think of writing a readable, pure-Python
peephole optimizer with bytecodehacks -- but if you could combine this
with, say, list comprehensions, I think that whole new vistas may open

[*] I think it would be necessary to rewrite TokenStream, but that's
not too bad.


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