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Newsgroups: comp.lang.ada
Subject: Re: Parallel Text Corpus Processing with Ada?
From: Georg Bauhaus <rm.tsoh+bauhaus@maps.futureapps.de>
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Date: Sun, 11 Nov 2007 16:54:40 +0100
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On Sun, 2007-11-11 at 09:23 +0100, Dmitry A. Kazakov wrote:

> Why necessarily RE? Or else why patterns? Patterns come at a high price.
> They are sufficiently slower than tailored string processing algorithms.

SPITBOL patterns serve "tailored string processing algorithms";
I don't quite understand how you could have more targetted algorithms
for large corpora. What do you have in mind?
For example, BreakX is hard to beat; I believe that your assessment that
"patterns are more powerful, but slower in matching"[1] is really true.

A few RE packages have a Boyer-Moore algorithm built in, and more.
How can string processing be substantially faster?

(I guess that the new Ada.Strings.Fixed.Index/5 subprograms are
an improvement, maybe depending on how string slices would otherwise
be passed to searches starting at some Position.)

[1] http://www.dmitry-kazakov.de/match/match.htm