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From: Lapo Luchini <lapo AT lapo DOT it>
Subject:  Re: Limited regex support in newlib cripples syntax highlighting  in nano
Date:  Tue, 02 Sep 2008 08:17:45 +0200
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Reini Urban wrote:
> 2008/8/1 Tomi Belan wrote as "Limited regex support in newlib cripples
> syntax highlighting in nano"
>> Cygwin regex.h implementation doesn't support some special sequences,
>> for example \< (beginning of word), \> (end of word) and \b (word
>> boundary). This causes a usability bug with the nano editor, which
>> uses these sequences extensively in most of its syntax highlighting
>> rules.
> 
> Posix regex is much faster then perl-style pcre regex. Syntax
> highlighter usually prefer fast over complete. So the term "crippled"
> should be used with care.
> 
> See e.g. http://swtch.com/~rsc/regexp/regexp1.html - Regular
> Expression Matching Can Be Simple And Fast (but is slow in Java, Perl,
> PHP, Python, Ruby, ...)  - which complains about the typical POSIX
> spencer implementation also.

Interesting paper!

Judging from the linked efficient implementations, it could be 
interesting to have TRE library <http://laurikari.net/tre/> in Cygwin.

But judging from our own "man regexp" it should already have 
back-references (??):
"Regexec is largely insensitive to RE complexity except that back 
references are massively expensive."



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