Ruby Method Overloading

benchmark.rb

require "benchmark/ips"
require_relative "./method_overloading"

class Foo
  include MethodOverloading

  def call(number)
    "foo #{number}"
  end
end

class Bar
  def call(number)
    "bar #{number}"
  end
end

foo = Foo.new
bar = Bar.new

Benchmark.ips do |x|
  x.report("method overloading") { foo.call(23) }
  x.report("method") { bar.call(23) }
  x.compare!
end

__END__

Warming up --------------------------------------
  method overloading    24.146k i/100ms
              method   305.480k i/100ms
Calculating -------------------------------------
  method overloading    225.254k (±13.5%) i/s -      1.111M in   5.053180s
              method      3.274M (± 3.5%) i/s -     16.496M in   5.045562s

Comparison:
              method:  3273590.9 i/s
  method overloading:   225253.9 i/s - 14.53x  (± 0.00) slower

foo.rb

require_relative "./method_overloading"

class Foo
  include MethodOverloading

  def call
    puts "foo"
  end

  def call(number)
    puts "foo #{number}"
  end
end

foo = Foo.new
foo.call # => "foo"
foo.call(23) # => "foo 23"

method_overloading.rb

module MethodOverloading
  def self.included(klass)
    klass.class_eval do
      @__method_overloading = {}

      def self.method_added(method_name)
        m = instance_method(method_name)
        method_id = [method_name, m.arity]

        @__method_overloading[method_id] = m
        undef_method method_name
      end

      def self.respond_to_matching?(method_name, *args)
        @__method_overloading.key?([method_name, args.count])
      end

      def self.matched_call(instance, method_name, *args, &blk)
        m = @__method_overloading[[method_name, args.count]]
        m.bind_call(instance, *args)
      end
    end
  end

  def method_missing(method_name, *args, &blk)
    super unless self.class.respond_to_matching?(method_name, *args, &blk)

    self.class.matched_call(self, method_name, *args, &blk)
  end

  def respond_to_missing?(method_name, *)
    self.class.respond_to_method?(method_name)
  end
end

If anyone wants to continue to improve this, https://github.com/dblock/ruby-overload