So regular expessions dont offer level1:basic unicode support?
See http://unicode.org/reports/tr18/

On Tue, Jan 10, 2012 at 06:07:13PM +0900, Yui NARUSE wrote:
> 
> Issue #5871 has been updated by Yui NARUSE.
> 
> 
> Martin Dürst wrote:
> > Shohei Urabe writes:
> > 
> > > Martin Dürst wrote:
> > > > Shouhei Urabe writes:
> > > > 
> > > > > Quite generally speaking you are advised not to use /i in Unicode.
> > > > 
> > > > Are there other examples where /i is advised against? If yes, please let's look at them and try to fix them, too.
> > > 
> > > /Dijkstra/i.match("DIJKSTRA") or something like that.
> > 
> > What about /Dijkstra/.match("Dijkstra") ?
> > $ ruby -e "puts /D\u0133kstra/.match('Dijkstra').inspect"
> > nil
> 
> It is not an issue of case equivalence.
> 
> > If this doesn't match without case equivalence, why should it match with case equivalence?
> > (I'm assuming that matching is transitive and that matching by /i should be a superset of matching without.)
> 
> irb(main):005:0> /[^a-z]/=~"A"
> => 0
> irb(main):006:0> /[^a-z]/i=~"A"
> => nil
> ----------------------------------------
> Bug #5871: regexp \W matches some word characters when inside a case-insensitive character class
> https://bugs.ruby-lang.org/issues/5871
> 
> Author: Gareth Adams
> Status: Rejected
> Priority: Normal
> Assignee: 
> Category: 
> Target version: 
> ruby -v: ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin10.8.0]
> 
> 
> =begin
> The following replacement, which should do nothing, has removed the upper- and lower-case "K"s and "S"s from the result:
> 
>     > "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".gsub(/[\W]/i,"")
>     => "ABCDEFGHIJLMNOPQRTUVWXYZabcdefghijlmnopqrtuvwxyz"
> 
> The result is correct (the same as the input string) if I remove either the character class:
>  
>     > "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".gsub(/\W/i,"")
>     => "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" 
> 
> or the case insensitive flag:
> 
>     > "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".gsub(/[\W]/,"")
>     => "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
> 
> This has been observed in two separate ruby 1.9 installs:
> 
> * ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-darwin10.8.0]
> * ruby 1.9.3p0 (2011-10-30 revision 33570) [x86_64-darwin11.2.0]
>   
> but works correctly in 1.8
> =end
> 
> 
> 
> -- 
> http://bugs.ruby-lang.org/

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