#!/usr/local/bin/ruby
module KMHash
  def method_missing(method, *params)
    method_string = method.to_s
    if (method_string[-1] == "="[0])
      self[method_string[0..-2]] = params.first
    else
      self[method_string]
    end
  end
end

# this works
dan = Hash.new.extend KMHash
dan.kogai = 'blogger'
p dan.kogai

# this throws an exception
matz = Hash.new
matz.yukihiro = 'rubyist'
p matz.yukihiro