[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [bug-grep] Re: grep: -i option not working i cronjobs

From: Aharon Robbins
Subject: Re: [bug-grep] Re: grep: -i option not working i cronjobs
Date: Sun, 14 Nov 2004 09:24:23 +0200

> > 2) convert the regular expression to match both cases for any literals
> > simply by expanding each alphabetic symbol to a character class of it's
> > lowercase and upper case forms: e.g, 'a' -> '[aA]', 'B'-> '[bB]', etc.
> > 
> > My guess is that for most cases, the second solution would be faster. But
> > that's just a semi-educated guess at the moment. Does anyone know better?
> I agree that (2) is the better solution.  It better matches the intended 
> meaning, and will work properly in situations like languages that have no 
> lower-case equivalent of a certain character, or have more than one 
> lower-case 
> version of a single upper-case character.

Careful here.  As I just recently learned, there are languages where
a lower case character is one byte and the upper case equivalent is a
multibyte character.  (Or vice versa, I don't remember.)  Thus, the
'a' -> '[aA]' solution is fine for ASCII, but doesn't generalize for other
character sets.  Or least not simply.


reply via email to

[Prev in Thread] Current Thread [Next in Thread]