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Date: Fri, 1 Oct 2010 11:38:53 +0200
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To: Adam Harvey <aharvey@php.net>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Re: RFC: Comparable interface
From: pierre.php@gmail.com (Pierre Joye)

hi Adam,

Thanks for writing and updating a RFC, always the best way to propose
new features :)

On Fri, Oct 1, 2010 at 10:38 AM, Adam Harvey <aharvey@php.net> wrote:
> On 30 September 2010 21:33, Adam Harvey <aharvey@php.net> wrote:
>> I've just written an RFC (with a patch against trunk) to implement a
>> Comparable interface similar to that in Java =97 in effect, allowing
>> object instances to be compared with semantics defined in userspace.
>> This is admittedly at the lower end of RFC-worthy proposals, but it's
>> a good system, and I'd like to see it used a little more. Plus, it's
>> good practice for the more interesting stuff to come. :)
>
> I've updated the RFC with a fresh patch that doesn't involve SPL at
> all and attempted to incorporate some of the questions and answers so
> far into the RFC. I've also added a section for concerns with the RFC;
> I've attempted to distil the concerns I've seen so far, but please
> feel free to edit that list if specific concerns are misrepresented or
> unrepresented.

Maybe to get a context about how other languages work (or do not work)
with these similar features, it could be interesting to look at the
python (2.5) documentation:
http://docs.python.org/release/2.5.2/ref/customization.html

As I would be in favor of having a compareTo interface for similar
objects, I worry a bit about comparing apple and pear. Yes, an apple
can be greater than a pear in real world but the wtf is somehow huge
in a php context. That's why I share Stas or Gustavo thoughts about
comparing instances of different classes (or with inheritance from
internal classes without a comparable implementation).

To be more precised, by "wtf", I mean that $a =3D=3D $b may not mean that
$b =3D=3D $a (as in python for example). That's something we should
consider carefully.

Cheers,
--=20
Pierre

@pierrejoye | http://blog.thepimp.net | http://www.libgd.org