source_for.rb

# My take on Mike's source_for method.
# (see http://pragmaticstudio.com/blog/2013/2/13/view-source-ruby-methods)
#
# (1) I named it 'src' rather than source_for (ok, I'm a lazy typer).
# (2) The edit function was broken out as a separate function.
# (3) The edit function is for emacs
# (4) If the method is not defined on the object, and the object 
#     is a class, then see if it is an instance method on the class.
#
# The fourth point allows my to say:
#
#      src(Person, :update)
# or   src(Person.new, :update)
#
def edit(file, line)
  `emacsclient -n +#{line} #{file}`
end

def src(object, method)
  if object.respond_to?(method)
    meth = object.method(method)
  elsif object.is_a?(Class)
    meth = object.instance_method(method)
  end
  location = meth.source_location
  edit(*location) if location
  location
rescue NameError => ex
  nil
end