A Typed Class in Ruby

typed.rb

require 'rtc'

class Post
  rtc_annotated

  typesig('@id: String')
  attr_accessor :id
  
  typesig('@title: String')
  attr_accessor :title

  typesig('@timestamp: Fixnum')
  attr_accessor :timestamp

  typesig("self.build: (Hash) -> Post")
  def self.build(attrs)
    post           = new.rtc_annotate("Post")
    post.id        = attrs.delete(:id)
    post.title     = attrs.delete(:title)
    post.timestamp = attrs.delete(:timestamp)
    post
  end
end

Post.build({id: "100", title: "Cool", timestamp: "100"})

# -> ruby typed.rb 
# /Users/mrb/.rbenv/versions/1.9.3-p545/lib/ruby/gems/1.9.1/gems/rtc-0.0.0/lib/rtc/runtime/method_check.rb:91:in `select_and_check_args': In method timestamp=, annotated types are [Rtc::Types::ProceduralType(10): [ (Fixnum) -> Fixnum ]], but actual arguments are ["100"], with argument types [NominalType(1)<String>] for class Post (Rtc::TypeMismatchException)
#   from method_wrapper.rb:41:in `timestamp='
#   from /Users/mrb/.rbenv/versions/1.9.3-p545/lib/ruby/gems/1.9.1/gems/rtc-0.0.0/lib/rtc/proxy_object.rb:470:in `method_missing'
#   from typed.rb:20:in `build'
#   from method_wrapper.rb:55:in `build'
#   from typed.rb:25:in `<main>'