From: Fearless Fool <r@...>
Date: 2010-12-26T16:42:35+09:00
Subject: converting traversal fn into Enumeration

I've not quite wrapped my head around Enumerations, but I suspect I'm
just being dense.  Assume the following small code fragment:
-----
TNode = Struct.new(:left, :right, :value)
class TNode

  def traverse(&block)
    left.traverse(&block) if left
    right.traverse(&block) if right
    yield(self)
  end

end
-----
... which lets me define a method such as:
-----
  def find_node(value)
    traverse { |node| return node if (node.value == value) } || nil
  end
-----
For somewhat didactic reasons, I'd prefer a method TNode#traversal(),
that returns an Enumerable, so I could do something like:
-----
  def find_node(value)
    traversal.find {|n| n.value == value}
  end
-----
... but as I mentioned, I haven't figured out the right way to structure
this.  Any hints?  Or is it not worth the effort?

TIA.

- ff

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