From: Vincent Fourmond <vincent.fourmond@9online.fr>
Date: 2007-01-12T18:22:49+09:00
Subject: Re: Why doesn't Ruby allow for overloaded methods within a class

Wes Gamble wrote:
> (from a Java refugee)
> 
> All,
> 
> I've done quite a bit of googling and read a bunch of posts about this,
> but I'm looking for a simple explanation of why Ruby doesn't support
> method overloading within a class to allow methods with the same name
> but different numbers of arguments.  I understand that you can't do
> method overloading with the same # of arguments since you don't know any
> "types" of input parameters when you invoke a method.
> 
> But...it seems like you could allow it for different numbers of input
> parameters.
> 
> Here's an example of what I mean:
> class Foo
>   def methname(x,y)
>     ...
>   end
> 
>   def methname(x, y, z)
>     ...
>   end
> end
> 
> I'm comfortable with how to implement this using a method with varargs
> and appropriate logic, and I'm aware of arguments that the methods
> should probably be different in name if their set of input parameters
> are of different size.
> 
> But it seems like this kind method overloading would be doable in Ruby.
> Is it possible?
> Is it not available because there's a feeling that it isn't needed?

  Use default arguments

  def methname(x,y, z = false)
    if z
    else
  end

  If false is a valid value for z, you can try z = :special
  if z == :special

  Moreover, most of the time, quite a bit of code is shared from the
2-args version to the 3-args version. Actually, if that is not the case,
it is probably a sign that the functionality shouldn't be regrouped
under a unique name.

  Cheers,

	Vince
-- 
Vincent Fourmond, PhD student
http://vincent.fourmond.neuf.fr/