From: Justin To <tekmc@...>
Date: 2008-06-11T02:04:10+09:00
Subject: Basic Tree Data Structure

class Tree
  attr_reader :value
  def initialize(value)
    @value = value
    @children = []
  end

  def <<(value)
    subtree = Tree.new(value)
    @children << subtree
    return subtree
  end

end

t = Tree.new("Parent")
child1 = t << "Child 1"
child2 = t << "Child 2"
child2 << "Grandchild 2.1"
ggc1 = child1 << "Grandchild 1.1"
ggc1 << "Great Grand Child 1.1.1"
ggc2 = child1 << "Grandchild 1.2"
ggc2 << "Great Grand Child 1.2.1"

class Tree
  def each
    yield value
    @children.each do |child_node|
        child_node.each { |e| yield e } # mainly confuesd at this point
      end
  end
end

t.each { |x| puts x }


Hi, I'm a little confused about the algorithm used to display each item
in a tree...

at: child_node.each { |e| yield e }

when does the block { |e| yield e } come into play? Does the each method
for child_node occur first?

Thanks in advance!
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