irbrc helper to print documentation

gistfile1.rb

class Object
  # list methods which aren't in superclass
  def local_methods(obj = self)
    (obj.methods - obj.class.superclass.instance_methods).sort
  end
  
  # print documentation
  #
  #   ri 'Array#pop'
  #   Array.ri
  #   Array.ri :pop
  #   arr.ri :pop
  def ri(method = nil)
    unless method && method =~ /^[A-Z]/ # if class isn't specified
      klass = self.kind_of?(Class) ? name : self.class.name
      method = [klass, method].compact.join('#')
    end
    system 'ri', method.to_s
  end
end