From: Xavier Noria <fxn@...>
Date: 2007-09-21T08:57:22+09:00
Subject: Re: Idiomatic Ruby for Array#extract / Range#length?

And yet another example that satisfies in addition

   zs < zs.succ for all zs in ZSquared

which would be an expected relationship between succ and <=>:

   class ZSquared
     include Comparable

     attr_reader :n, :m

     def initialize(n, m)
       @n, @m = n, m
     end

     def succ
       self.class.new(n+1, m)
     end

     def <=>(zs)
       [self.m, self.n] <=> [zs.m, zs.n]
     end
   end

   a = ZSquared.new(0, 0)
   b = ZSquared.new(0, 1)

   puts a < b # true

   length = 0
   (a .. b).each do |c|
     length += 1
     puts length
   end

   # be prepared to send Ctrl-C

I guess that's enough for today at 1:57 AM.

-- fxn