Ruby and Recursive Send

Some dynamic languages have the ability to call an arbitrary method of an object. The name of the method to be called is usually stored inside a string.

Ruby is no different. You use Object#send to call a method:

"5".send(:to_i)   # => 5

This isn't that useful for a small thing like that example there, but for more sophisticated applications this can save you a lot of typing.

For something I'm working on, I have some code that gets repeated a lot on different return results of an object. So I figured I'd just stick all the things I had to do in a string, iterate over the string calling send. However some of the properties I wanted were a little complex, as in they were calling the methods of a return result of a method. For example (something I may have used on my freegamage site):

["genre", "user.name"].each do |method|
  game.send(method)
end

Unfortunately the "user.name" property is not actually a method of game, so it fails.

We have a solution though:

class Object
  def send_r(method)
    method.split(".").inject(self) { |ob, meth| ob.send(meth) }
  end
end

This little method assumes you're using something like "method1.method2.method3..." when you call it, and then recursively calls each method on the previous method's return value.