From: "phluid61 (Matthew Kerwin)" <matthew@...>
Date: 2012-12-19T08:25:55+09:00
Subject: [ruby-core:50970] [ruby-trunk - Bug #4044] Regex matching errors when using \W character class and /i option


Issue #4044 has been updated by phluid61 (Matthew Kerwin).


ben_h (Ben Hoskings) wrote:
> But, I'm not sure how [^\W] should treat these characters:
> 0x00DF (Latin small letter sharp s) 
> 0x017F (Latin small letter long s)
> 0x212A (Kelvin sign)

Can you just fall back on the Unicode categories?  If we define "word characters" as Letters and Numbers, U+212A is {Lu} and thus a word character.  Similary U+017F is {Ll}.

Seems a bit weird in the case of Kelvin (also the Angstrom Sign U+212B = {Lu}) but at least Unicode is a fixed and universally accessible standard.
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Bug #4044: Regex matching errors when using \W character class and /i option
https://bugs.ruby-lang.org/issues/4044#change-34836

Author: ben_h (Ben Hoskings)
Status: Feedback
Priority: Normal
Assignee: naruse (Yui NARUSE)
Category: core
Target version: 1.9.2
ruby -v: ruby 1.9.2p0 (2010-08-18 revision 29036) [x86_64-darwin10.4.0]


=begin
 Hi all,
 
 Josh Bassett and I just discovered an issue with regex matches on ruby-1.9.2p0. (We reduced it while we were hacking on gemcutter.)
 
 The case-insensitive (/i) option together with the non-word character class (\W) match inconsistently against the alphabet. Specifically the regex doesn't match properly against the letters 'k' and 's'.
 
 The following expression demonstrates the problem in irb:
 
     puts ('a'..'z').to_a.map {|c| [c, c.ord, c[/[^\W]/i] ].inspect }
 
 As a reference, the following two expressions are working properly:
 
     puts ('a'..'z').to_a.map {|c| [c, c.ord, c[/[^\W]/] ].inspect }
     puts ('a'..'z').to_a.map {|c| [c, c.ord, c[/[\w]/i] ].inspect }
 
 Cheers
 Ben Hoskings & Josh Bassett
=end



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