proof_of_concept.rb

# In a clojure REPL you can get information about a function like so:
# user=> (doc identity)
# -------------------------
# clojure.core/identity
# ([x])
#   Returns its argument.
# nil
# user=> (source identity)
# (defn identity
#   "Returns its argument."
#   [x] x)
# nil
#
# I've become very dependent on these helpers when writing clojure.
# I want this same goodness in IRB when I'm hacking ruby code.  This is a
# proof of concept of using YARD to get #source and #doc helpers in IRB.
# This requires ruby 1.9 and the latest version of YARD. See this gist for
# 1.8 compat: http://gist.github.com/357264
#
#
# Many thanks to lsegal for making this so simple with YARD and showing me
# how to do it.

require 'yard'

module YardObject
  def source; yard_object.source end
  def docstring; yard_object.docstring end

  private

  def yard_object
    fname = source_location[0]
    @@file_cache ||= {}
    unless @@file_cache[fname]
      @@file_cache[fname] = true
      YARD.parse(fname)
    end
    @yard_object ||= YARD::Registry.at(owner.name + '#' + name.to_s)
  end
end

class Method; include YardObject end
class UnboundMethod; include YardObject end

class Foo

  # This is a very cool method.  It does a ton.
  def bar
    puts "Hello!" # Stuff
  end

end

def source(method_signature)
  yard_info(method_signature, :source)
end

def doc(method_signature)
  yard_info(method_signature, :docstring)
end

def yard_info(method_signature, info)
  puts "-------------------------"
  puts  method_signature
  puts YARD::Registry.at(method_signature).send(info)
end

f = Foo.new
puts f.method(:bar).docstring
puts f.method(:bar).source
# This is a very cool method.  It does a ton.
# def bar
#   puts "Hello!" # Stuff
# end
#
puts "\n\nIRB session with this goodness\n\n"

puts "doc \"Foo#bar\""
puts doc("Foo#bar")
puts "\n\n\n"

puts "source \"Foo#bar\""
puts source("Foo#bar")
puts ""

# IRB session with this goodness
#
# doc "Foo#bar"
# -------------------------
# Foo#bar
# This is a very cool method.  It does a ton.
#
# source "Foo#bar"
# -------------------------
# Foo#bar
# def bar
#   puts "Hello!" # Stuff
# end