From: Christian Neukirchen <chneukirchen@...>
Date: 2005-04-27T02:35:03+09:00
Subject: Re: Announcing Reg 0.4.0

Florian Gro� <florgro@gmail.com> writes:

> David A. Black wrote:
>
>> extending the system so that it could match, for example,
>> "an array of objects that respond to '[]'" (or something along those
>> lines)?
>
> I wonder if he could just support objects that implement === which
> would give you Range and Module support and ruby-contract support for
> free.
>
> But how is this related to your quote at all? ruby-contract offers a Check::Quack[:message] adaptor that implements === via respond_to?() -- 
> I wonder if it would be a good idea to define Symbol#=== which would
> be used like this:
>
> first = case obj
>    when :first then
>      obj.first
>    when :fetch then
>      obj.fetch(0)
>    when :at then
>      obj.at(0)
>    when :[] then
>      obj[0]
> end

While I can see your intention, please don't do that.  Often, people
want to compare Symbols and Symbols (they are perfect for that).  It
is already very confusing that String !=== String (what is the most
elegant way to case compare classes against classes, btw?).

case obj.quack
  when :first
  when :fetch
  ...
end

would be nice to have, though.

-- 
Christian Neukirchen  <chneukirchen@gmail.com>  http://chneukirchen.org