class Hash

  # Same as #update_each, but deletes the key element first.
  def replace_each  # :yield:
    dup.each_pair{ |k,v| delete( k ); update( yield(k,v) ); }
    self
  end

end


#  _____         _
# |_   _|__  ___| |_
#   | |/ _ \/ __| __|
#   | |  __/\__ \ |_
#   |_|\___||___/\__|
#
=begin test

  require 'test/unit'

  class TCHash < Test::Unit::TestCase

    def test_replace_each
      a = { :a => 1, :b => 2, :c => 3 }
      e = { :a => 2, :b => 3, :c => 4 }
      a.replace_each{ |k,v| { k => v+1 } }
      assert_equal( e, a )
    end

  end

=end