Overriding Hash#[] from a module

whoopey.rb

# So, this version is not at all mine, it's one from @samuelkadolph.
# (Just for the record.)

class MyHash < Hash
  def initialize(hash = {})
    super()
    merge!(hash) if hash
  end

  def [](key)
    return super(key.to_s) if key?(key.to_s)
    return super(key.to_sym) if key?(key.to_sym)
  end
end

module M
  def self.included(klass)
    klass.class_eval do
      alias_method :original_indexer, :[]
      alias_method :[], :new_indexer
    end
  end

  def new_indexer(key)
    return original_indexer(key.to_s) if key?(key.to_s)
    return original_indexer(key.to_sym) if key?(key.to_sym)
  end
end

class MyHash2 < Hash
  include M
end

h1 = MyHash.new(:a => 2)
h1["a"] # => 2

h2 = MyHash2.new
h2[:a] = 2
h2["a"] # => 2