From: Assaph Mehr <assaph@...>
Date: 2004-12-13T10:22:20+09:00
Subject: Re: Avoiding if requires type mutation -- evil.rb?

Why make the distinction between leaf and node? A leaf is just a node
without children.

Why not simply have something like (code written to email, not
checked):

class Node
attr_accessor :children

def initialize
children = []
end

def leaf? children.size.zero? end
end

And use it as

if node.leaf?
# do leafy stuff
  else
     # do branchy stuff
  end