[climacs-devel] cl-automaton -- patch to print minimal forms of regexps

[Derek Peschel]

On Sat, Sep 24, 2005 at 05:57:09AM -0700, Aleksandar Bakic wrote:
> BTW, I am not sure if this is of interest to you: have you thought about
> extending cl-automaton with groupings and/or back-references? In

Yes, I thought of it as a feature.  First I'd like to understand the syntax
and write a syntax class for it.  Even though that would be a small
improvement, it's a feature I've wanted to see for a long time.  Right now,
for the most part, Automaton has a pleasantly simple syntax.  Character
classes are the only exception I know about.

> http://jp.franz.com/base/seminar/2004-06-10/Franz-e1.pdf, on page 8 it is
> claimed that the former is tricky and the latter is difficult for a DFA-based
> regexp engine.

I don't know how regexp libraries these days are implemented, but some of them
use hybrids of DFA and NFA ideas.  It might be easiest to change to a pure
NFA implementation and then "hybridize" it later.  On the other hand,
there are a few other regexp libraries in LISP and it might really be easiest
to switch to one of them.

-- Derek