dynamic define method with ruby 1.8.7

def.rb

# -*- coding: utf-8 -*-
class Object

  def self.define_method(funcname, *params, &blk)
    @@methods ||= {}
    @@methods[funcname.to_sym] = blk
    class_eval(<<DEFINE)
def #{funcname} #{params.join(', ')}
  b = binding
  def b.method_missing(varname, *args)
    $temporary_args = args
    if args.empty?
      ret = eval("\#\{varname\}")
    else
      ret = eval("\#\{varname\}(*$temporary_args)")
    end
    $temporary_args = nil
    ret
  end
  b.instance_eval(&(@@methods[:#{funcname.to_sym}]))
end
DEFINE
  end

  def define_singleton_method(funcname, *params, &blk)
    @instance_methods ||= {}
    @instance_methods[funcname.to_sym] = blk
    instance_eval(<<DEFINE)
def #{funcname} #{params.join(', ')}
  b = binding
  def b.method_missing(varname, *args)
    $temporary_args = args
    if args.empty?
      ret = eval("\#\{varname\}")
    else
      ret = eval("\#\{varname\}(*$temporary_args)")
    end
    $temporary_args = nil
    ret
  end
  b.instance_eval(&(@instance_methods[:#{funcname.to_sym}]))
end
DEFINE
  end

end

if __FILE__ == $PROGRAM_NAME
  require 'test/unit'

  class TestDefineMethod < Test::Unit::TestCase

    def setup
      str = "hello"
      Object.define_method(:homuhomu_method, :arg0, :arg1) {
        arg0 + arg1
      }
      @obj = Object.new
      @obj.define_singleton_method(:homuhomu_singleton_method, :arg0, :arg1) {
        arg0 + arg1
      }
      @obj.define_singleton_method(:homuhomu_wrapper, :arg0, :arg1) {
        homuhomu_singleton_method arg0, arg1
      }
      @obj.define_singleton_method(:homuhomu_closure) {
        str
      }
    end

    def test_define_method
      assert_equal(10, @obj.homuhomu_method(5, 5))
    end

    def test_define_singleton_method
      assert_equal(10, @obj.homuhomu_singleton_method(5, 5))
    end

    def test_wrapper
      assert_equal(10, @obj.homuhomu_wrapper(5, 5))
    end

    def test_closure
      assert_equal("hello", @obj.homuhomu_closure)
    end

    def test_string
      assert_equal("abcdefg", @obj.homuhomu_method("abcd", "efg"))
    end

    def test_object
      assert_equal([1, 2, 3, 4, 5], @obj.homuhomu_method([1, 2], [3, 4, 5]))
    end

  end

end