From: Robert Klemme <bob.news@...>
Date: 2006-02-06T23:38:20+09:00
Subject: Re: Merging regular expressions

Dave Burt wrote:
> Anthony Durity asked:
>> Imagine I have a bunch of n RegExps r[] - they could be any valid
>> ruby Regexps.
>> Say I want to match each of them in turn to a certain something s to
>> make sure that no two Regexps in the list both match s.
>> Now say that I want a meta regular expression m that is all the
>> Regexps merged together so that the following pseudo code wroks,
>> 
>> m = MetaRegExp.new
>> for each r { [i] m.add(r[i]) } # add makes sure that no two RegExps
>> would match the same input
>> 
>> m =~ s # returns an int representing which of the n original RegExps
>> would have matched
> 
> Why not just use the array of regexps like this?
> 
> matches = r.map{|i| r =~ s }
> matches.index(matches.select{|i| i }[0])  # returns the int you're
> after 

I guess you rather meant

matches = r.map {|i| i =~ s}
error = matches.compact.size != 1

Kind regards

    robert