Messages

message.rb

## This is an experiment in stronger message handling protocols in Ruby.

module BasicProtocol

  def method_missing(method, *args, &block)
    if respond_to? :handle_missing_method
      return handle_missing_method(method, *args, &block)
    else
      return { error: "no method found!" } 
    end
  end

  def respond_to_missing?(method_name, include_private = false)
    method_name.to_s != "handle_missing_method" || super
  end

end


module DerpProtocol
  include BasicProtocol

  def wat message
    # silly precondition
    if message[:foo].nil?
      return { error: 'precondition fail whale!' }
    end

    result = super

    # silly postcondition
    if result[:success] != true
      return { error: 'postcondition fail whale!' }
    end

    # result
    return result
  end

end


class Derp
  prepend DerpProtocol

  def wat message
    { success: true }
  end

end

class CustomErrorDerp
  prepend DerpProtocol

  def handle_missing_method method, *args
    return { error: "custom no method found!" } 
  end

end


# run program

foo = Derp.new
puts foo.wat foo: 'wat'
puts foo.wat something: 'wat'
puts foo.abc_method

foo2 = CustomErrorDerp.new
puts foo2.abc_method

# expected output:
#
# {:success=>true}
# {:error=>"precondition fail whale!"}
# {:error=>"no method found!"}
# {:error=>"custom no method found!"}
#