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Date: Tue, 17 Aug 2010 09:04:26 +0100
Message-ID: <AANLkTikz2r3-ukyJfSLJDAV04wgq=a7QD_+SgfDn7Krd@mail.gmail.com>
To: Jingcheng Zhang <diogin@gmail.com>
Cc: php-dev <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Static initialization block support in Class?
From: rquadling@gmail.com (Richard Quadling)

On 17 August 2010 08:39, Jingcheng Zhang <diogin@gmail.com> wrote:
> Hello internals,
>
> I wonder whether it is possible to implement "static initialization block=
"
> feature in PHP, for example:
>
> <?php
> class Foo {
>
> }
> class Bar {
> =C2=A0 =C2=A0public static $baz =3D 'baz';
> =C2=A0 =C2=A0public static $foo;
> =C2=A0 =C2=A0static {
> =C2=A0 =C2=A0 =C2=A0 =C2=A0// After loading this file, self::$foo is init=
ialized as a Foo
> instance.
> =C2=A0 =C2=A0 =C2=A0 =C2=A0self::$foo =3D new Foo();
> =C2=A0 =C2=A0}
> }
> ?>
>
> Currently we have to do this outside the class definition as static varia=
ble
> initialization is only limited to constant values.
> However in some circumstance, "dynamic" initialization of static variable=
 is
> expected and meaningful.
>
> Thanks in advance!
>
> --
> Best regards,
> Jingcheng Zhang
> P.R.China
>

Implementing a singleton method is a common solution and one that is
well understood and documented.

Another option would be to put the initialisation immediately after
the class definition, so once the class is loaded, a static instance
is prepared. This saves the consumer of the class from having to do 1
additional line of code.

Or you could load the public static methods with a JIT call to prepare
the static instance. Overhead is that every call will have to test
self::$instance


There is probably some argument against "statics" being "dynamic"
though ... not my area of expertise to argue either way.

--=20
Richard Quadling.