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Reply-To: Derrell.Lipman@UnwiredUniverse.com
Date: Mon, 09 May 2005 12:17:32 -0400
In-Reply-To: <is8k2su0.fsf@random.internal> (Derrell Lipman's message of "Fri,
	05 Nov 2004 10:55:51 -0500")
Message-ID: <4qdcz84j.fsf@random.internal>
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Subject: Re: new overloading feature?
From: Derrell.Lipman@UnwiredUniverse.com

Derrell.Lipman@UnwiredUniverse.com writes:

Leonardo Pedretti <lpedretti@suserver.com> writes:

> I would like (for code cleanliness purposes) to make 'new' return a
> reference to an already created object under certain circumstances without
> using a factory, is it possible?

A number of months ago, I proposed a similar feature, implemented as
overloading a __new() function.  At the time, it seemed I was the only one who
wanted it, but your request is for a feature identical to my request.  Here's
my previous message.  (The whole thread can be found under the subject "new
overloading feature?" from 5 Nov 2004).  I'd love for this to be revisited now
that there's someone else with a similar desire.

My previous proposal:

> I came across an interesting desire today.  I'd like to create a new class
> instance if an only if a "key" value does not already exist.  This key value
> could be looked up in a database, in an array, etc.
>
> The following contrived example shows use of a proposed __new() overload
> function which would be called BEFORE the constructor, and could chose to
> return a newly constructed object (by calling __construct()) or to return an
> already existing object.
>
> One could certainly call a function which searched for the key value and only
> instantiated a new object if the existing one was not found, but this seems
> cleaner.
>
> Thoughts?
>
> <?php
>
> class X
> {
>     static          $allX = array();
>     var             $val;
>
>     function __construct($val)
>     {
>         $this->val = $val;
>         X::$allX[] =& $this;
>     }
>
>     function __new($val)
>     {
>         foreach (X::$allX as $x)
>         {
>             if ($x->val == $val)
>             {
>                 return $x;
>             }
>         }
>
>         return __construct($val);
>     }
> }
>
> $try1 = new X(23);              /* would return $allX[0] reference */
> $try2 = new X(42);              /* woudl return $allX[1] reference */
> $try3 = new X(23);              /* would return $allX[0] reference */
> ?>