From: gabriele renzi <surrender_it@...>
Date: 2005-12-12T03:32:37+09:00
Subject: Re: lib for optional static typing

Austin Ziegler ha scritto:
> On 11/12/05, gabriele renzi <surrender_it@-remove-yahoo.it> wrote:
> 
>>Oh, the nicety of
>>  def Math.sqrt(Positive p)
>>:)
> 
> 
> Hm. No. That would end up requiring a significant change to Ruby,
> because sqrt is legal on negative numbers, as long as you have
> imaginary (complex) number support available. 

yeah, I'm not really suggesting changing Math.sqrt, just an example.

> So you would then have
> to have overloading instead of simple overriding as Ruby currently
> does, because you'd need def Math.sqrt(Positive p) and def
> Math.sqrt(Negative p).
> 
> Overloading, I have come to believe, is a nightmare compared to
> duck-typing. That's one of the reasons I oppose *anything* that
> threatens to put it into Ruby, because it's a mess.
> 

I was thinking of multimethods, more than simple overloading C++ style, 
but I'm not sure if that belongs to ruby so I won't argue on this.

But would you please explain why do you think multiple dispatch is a bad 
thing, it would be interesting to hear the reasons that brought you to 
this conclusion.