1  >> $:.grep(%r{/gems/([^/]+-[0-9\.]+)/lib$}){$1}
   2  => ["addressable-2.0.2", "merb-auth-slice-password-1.0.8.1", "json-1.1.4.1", "extlib-0.9.10", ...

methopara is a gem that enables us to use Method#parameters with Ruby-1.9.1. It was originally made by @ko1_twitter, the creater of YARV, at the previous meet-up of asakusa.rb.

And this time, I added an interface to use it for UnboundMethod. Now you can use UnboundMethod#parameters with new methopara, like this.

   1  require 'rubygems'
   2  require 'methopara'
   3  
   4  class Foo
   5    def foo(a,b) end
   6  end
   7  Foo.instance_method(:foo).parameters
   8  #=> [[:req, :a], [:req, :b]]

Enjoy!

Yesterday (Feb 10, 2009), asakusa.rb took place at Akihabara, Tokyo. asakusa.rb is a rubyist community that is based on Asakusa.

In the monthly meet-up of that community, @ko1_twitter wrote a code snippet. This snippet is a kind of backport of Method#parameters for Ruby-1.9.1. His quick job led a way for merbists to change merb to be corresponding to Ruby-1.9.1. He named his work "methopara". It stands for METHOd PARAmeters.

And I made it as a gem for ease of use. Now we can use it by the command below.

   1  % sudo gem install methopara --source http://merbi.st

Usage is as follows.

   1  >> require "rubygems"
   2  >> require "methopara"
   3  >> def foo(a,b=nil,&c) end
   4  >> method(:foo).parameters
   5  => [[:req, :a], [:opt, :b], [:block, :c]]

This gem is only for Ruby-1.9.1. Because Ruby18x have merb-action-args, and Ruby-1.9.2 and its successors will have built-in Method#parameters.

Enjoy!

See Also

• methopara
• methopara on github
• @maiha's gist