Class typed methods in Ruby

class_typed_methods.rb

class Class
  def define_typed_method(name, types, &block)
    define_method(name) do |args|
      args.each do |(arg, value)|
        raise ArgumentError.new("Wrong class for #{arg}") unless value.is_a?(types[arg])
      end
      block.call(args)
    end
  end
end

class MyThing
  define_typed_method(:foo, bar: String, baz: Integer) do |args|
    puts args[:bar]
    puts args[:baz]
  end
end

thing = MyThing.new
thing.foo(bar: "woof", baz: 123)
thing.foo(bar: "woof", baz: "123") # Boom!