From: walter a kehowski <wkehowski@...>
Date: 2005-08-13T06:31:11+09:00
Subject: Re: cartesian product - next to last version

Hello,

Yielding the values is certainly a good idea, but it makes the code a
lot bigger. Anyhow, here is the recursive, yielding version.

def cartprod(base, *others)
  if block_given?
    if others.empty?
      base.each{|a| yield [a]}
    else
      base.each do | a |
cartprod(*others) do | b |
  yield [a, *b]
end
      end
    end
    nil # <--Why?
  else
    return base.map{|a|[a]} if others.empty?
    others = cartprod(*others)
    base.inject([]) { | r, a | others.inject(r) { | r, b | r << ([a, 
*b]) } }
  end
end

-- 
http://ruby.brian-schroeder.de/

## Question: Why the nil?