From: Guillaume Marcais <guslist@...>
Date: 2004-05-15T01:02:48+09:00
Subject: Re: Regexp Error?

On Fri, 2004-05-14 at 11:47, Simon Strandgaard wrote:
> <advertisement>
> my engine uses loop-detection, it thus outputs more desired results.
> http://raa.ruby-lang.org/list.rhtml?name=regexp
> 
> For instance my engine outputs
> 	/a(a|)*/ ~= 'aaab'     -> ['aaa', 'a']
> 	/a(|ab)*b/ ~= 'aaabbb' -> ['aabb', 'ab']
> 	/x(y?)*z/ ~= 'xyz'     -> ['xyz', 'y']
> 	/x(y{0,2})*z/ ~= 'xyz' -> ['xyz', 'y'] 
> If you try the same examples with Gnu or Oniguruma, you will see the last elements
> are empty, I guess this is because they use the empty-token concept.
> </advertisement>

Huh? False advertisement?

[gus@comp tmp]$ cat regexp.rb
p /a(a|)*/.match('aaab').to_a
p /a(|ab)*b/.match('aaabbb').to_a
p /x(y?)*z/.match('xyz').to_a
p /x(y{0,2})*z/.match('xyz').to_a
[gus@comp tmp]$ ruby regexp.rb
["aaa", "a"]
["aabb", "ab"]
["xyz", "y"]
["xyz", "y"]
[gus@comp tmp]$ ruby -v
ruby 1.8.1 (2004-03-31) [i586-linux-gnu]

Guillaume.