From: Stefano Crocco <stefano.crocco@...>
Date: 2011-02-01T18:21:45+09:00
Subject: Re: Decreasing range?

On Tuesday 01 February 2011 17:43:44 Stefano Grioni wrote:
> Thank you both, I feel ashamed that I didn't think about "downto" ..
> Concerning my more general question, do you have any clue about why
> decreasing ranges behave the way they do?
> 
> Thank you

Range#each calls the #succ method of the starting element to get the new one 
and goes on like this until the next element is greater than the last. If 
Range#each were written in ruby, I think it could be something like this (it's 
just a guess, I didn't look at the actual code):

class Range
  def each
    current = @start
    while (current <=> @end) < 1
      yield current
      current = current.succ
    end
  end
end

In your case @start would be 4, while @end would be 1. Since 4 is greater than 
1, the block is never called.

Stefano