Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:64642
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.215.42 as permitted sender)
MIME-Version: 1.0
In-Reply-To: <102501cdecf9$e427d540$ac777fc0$@starin.biz>
References: <102501cdecf9$e427d540$ac777fc0$@starin.biz>
Date: Mon, 7 Jan 2013 18:18:20 +0100
Message-ID: <CAF+90c8Gi85jSBJHKKm0C3WyYAuaAT8daVaYVzQ79jFQVo0w6g@mail.gmail.com>
To: nathan@starin.biz
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=f46d04083e331358fc04d2b6048c
Subject: Re: [PHP-DEV] new Class ReflectionZVal
From: nikita.ppv@gmail.com (Nikita Popov)

--f46d04083e331358fc04d2b6048c
Content-Type: text/plain; charset=ISO-8859-1

On Mon, Jan 7, 2013 at 6:10 PM, <nathan@starin.biz> wrote:

> I wanted some thought from you guys about the idea of giving PHP scripts
> the
> ability to read some internal information about variables such as ZVals.
>
>
>
> The idea of how this reflection class would work would be something like:
>
>
>
> Class ReflectionZVal {
>
>     // Retains info about the variable referenced
>
>     function __construct(&$variable);
>
>     // Returns if the referenced variable
>
>     function valueExists();
>
>     // Returns a ref to the variable or throws error if value is gone.
>
>     function &getValue();
>
>     // Returns the reference count of the variable
>
>     function getRefCount();
>
>     // Returns the current type associated with the referenced variable
>
>     function getType();
>
>     // Returns bool of if getValueReflection() is callable. (see note
> below)
>
>     function isValueReflectable();
>
>     // Returns a new instance of ReflectionZVal for the value of variable
> passed in construct. (returns null and throws error if value is not a ref
> of
> a variable)
>
>     function getValueReflection();
>
> }
>
>
>
> The idea of this class would give PHP the ability to read reference count
> info and have read-only access to values stored in variables without
> causing
> PHP to not be able to use the internal garbage collector. An example of how
> this could be useful would be if you had a class structure that matched a
> database table structure. Every time a new record of the table was returned
> it constructed a new object. It is more practical to have the class store
> each object that was constructed into a static variable attached to each
> class structure and when a new record is requested it first checks to see
> if
> the object with the same row has already been constructed and use/update
> that object instead of making (possibly) many duplicates. This gives the
> code structure the ability that if the same record was requested then later
> in the execution the same row was requested again and modified it would
> also
> modify it everywhere that object/row was already requested. The issue with
> this structure is that php's garbage collector will never clean up those
> constructed objects because the class needs a reference to them and cannot
> know if other places in the code has references to them.
>
>
>
> If a reflection like this one was available it would give the ability to
> contain a reference to variables/pointers without increasing the reference
> count. It would allow a class structure (like stated above) to call it's
> own
> garbage collector every once in a while to clean up those ReflectionZVal
> objects by checking the result of ReflectionZVal:: valueExists ().
>
>
>
> Is there anything obvious (limitation wise) that I am missing or is this
> RFC'able?
>
>
>
> Software Developer
>
> Nathan Bruer
>

I think what you are looking for here is a weak ref. See
http://pecl.php.net/package/Weakref

Nikita

--f46d04083e331358fc04d2b6048c--