From: Martin DeMello <martindemello@...>
Date: 2004-07-14T02:57:21+09:00
Subject: Re: Ruby quickies and useful idioms

Gavin Kistner <gavin@refinery.com> wrote:
> On Jul 12, 2004, at 1:47 AM, Martin DeMello wrote:
> > I've found this useful on several occasions
> >
> > class Array
> >   include EnumerableOperator
> >   def all_pairs
> >     a = size-1
> >     for i,j in product(0..a, 0..a, proc {|i,j| i < j})
> >       yield at(i), at(j)
> >     end
> >   end
> > end
> 
> It's too early in the morning for me to decode this. Is this the same 
> as my Array#each_unique_pair method documented here:
> 
> http://phrogz.net/RubyLibs/rdoc/classes/Array.html#M000061
> 
> If so, the implementation which doesn't require anything else is simply:
> 
> class Array
>          def each_unique_pair
>                  self.each_with_index{ |a,i|
>                          self[(i+1)..-1].each{ |b| yield a,b }
>                  }
>          end
> end

Heh - so it is :) Mine was basically the translation from the list
comprehension. 

martin