From: Dave Thomas <dave@...>
Date: 2003-04-24T12:26:54+09:00
Subject: Re: grep and regular expressions in ruby

Krishna Dole wrote:
> I'm quite taken with ruby, but recently I ran into trouble using grep. I
> have two questions: first, is there a way to call grep with multiple
> regexps? For example, if you had
> 	ar = ["cat", "dog", "smallcat"]
> 
> and you only wanted strings matching  both "small" and "cat", in perl I
> think you could do something like
> 	ar2 = grep(( /cat/ and /small/ ), ar );
> 
> but in ruby it seems like you have to call grep twice
> 	ar2 = ar.grep(/cat/).grep(/small/)
> 
> is there a more elegant solution?

Have you had a look at lib/eregexp? It doesn't quite do what you need, 
but a couple of quick additions makes it work:

require 'eregex'
class RegOr
   def ===(other)
     self =~ other
   end
end
class RegAnd
   def ===(other)
     self =~ other
   end
end

ar = [ "cat", "dog", "catdog", "dogcat" ].grep(/cat/&/dog/)



Cheers


Dave