Re: compiling case insensitive regular expressions

glen herrmannsfeldt <gah@ugcs.caltech.edu>
Wed, 3 Nov 2010 01:22:47 +0000 (UTC)

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compiling case insensitive regular expressions armelasselin@hotmail.com (Armel) (2010-11-01)
Re: compiling case insensitive regular expressions gah@ugcs.caltech.edu (glen herrmannsfeldt) (2010-11-03)
Re: compiling case insensitive regular expressions benhanson2@icqmail.com (2010-11-03)
Re: compiling case insensitive regular expressions armelasselin@hotmail.com (Armel) (2010-11-04)
Re: compiling case insensitive regular expressions rsc@swtch.com (Russ Cox) (2010-11-04)
Re: compiling case insensitive regular expressions gah@ugcs.caltech.edu (glen herrmannsfeldt) (2010-11-05)
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From: glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups: comp.compilers
Date: Wed, 3 Nov 2010 01:22:47 +0000 (UTC)
Organization: A noiseless patient Spider
References: 10-11-004
Keywords: lex
Posted-Date: 03 Nov 2010 23:44:36 EDT

Armel <armelasselin@hotmail.com> wrote:


> I need to compile regular expressions which are case insensitive,
> there are two cases, the part which must be matched case insensitvely
> might be just a portion but it can be the entire RE as well. The RE
> will be Unicode enabled and must be compiled to AFD.


Another way to do it, which I have seen used in the Paracel
FDF/TextFinder hardware search processor is to supply a bit mask for
each character being compared. Only bits with a '1' in the mask are
used in the comparison. (Bitwise AND with the mask, and compare to
the previously masked query character.)


-- glen



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