From: Brian Candler <B.Candler@...>
Date: 2004-10-04T23:37:09+09:00
Subject: Re: Too Many Ways?

On Mon, Oct 04, 2004 at 11:08:42PM +0900, trans.  (T. Onoma) wrote:
> Agreed. The reason I've gone the other way is b/c of this kind of thing:
> 
>   def ducky_method(a,b,c,d,e)
>   end
> 
>   ...
> 
>   case method(:ducky_method).arity
>   when 5
>   when 4
>   when 3
>   ...

Ugh... fortunately I've never had to write code like that :-) Especially
with the nasty overloading of negative values: -3 means 2..infinity. (Or is
it 4..infinity? I have to think about it every time. Remember, -1 means 0 to
infinity, obviously. So -3 is 2 to infinity. Got that?)

Anyway, I would hope that those methods would be declared as

  def ducky_method(a,b,c)
  def ducky_method(a,b,c,d=99)
  def ducky_method(a,b,c,d=99,e=123)

and that you would therefore know that a call with 3 parameters makes sense.
Otherwise, perhaps those methods should have completely different names, if
they do different things altogether (i.e. if it has two legs it's a goose,
if it has 4 legs it's a mongoose)

> > I quite like your suggestion of &blk=nil though. At the moment in Ruby the
> > presence/absence of a block makes no difference, until you try to 'yield'
> > when no block is given. In particular, you can pass a block to a method
> > which doesn't expect one; I've been caught by that before!
> 
> Yes, I like it _better_ too. But like matz said it would break a good bit of 
> code :( 

Perhaps these things are up for grabs in 2.0 though.

Regards,

Brian.