erebot / callable-wrapper
Callable wrapper for PHP < 5.4.0
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Requires
- php: >=5.3.0
- ext-spl: *
Requires (Dev)
This package is not auto-updated.
Last update: 2024-10-24 23:54:20 UTC
README
Warning
This component is now deprecated and is unneeded in newer versions of PHP. Do not use it in new code.
Installation
Download the composer.phar executable or use the installer.
$ curl -sS https://getcomposer.org/installer | php
Create a composer.json
that requires Erebot's Callable component.
{ "require": { "erebot/callable-wrapper": "dev-master" } }
Run Composer.
$ php composer.phar install
Usage
To use the wrapper, first include composer's autoloader and call
Erebot\\CallableWrapper::initialize()
, this will make sure everything
is set up properly.
Now, use Erebot\\CallableWrapper::wrap()
every time you want to execute
some callable code while using the callable
typehint.
<?php // Load composer's autoloader require_once PROJECT_ROOT . DIRECTORY_SEPARATOR . 'vendor' . DIRECTORY_SEPARATOR . 'autoload.php'; // Initialize the wrapper Erebot\CallableWrapper::initialize(); // Define a function/method that uses the "callable" typehint // as you normally would, even for PHP 5.3.x. function invokeCode(callable $code) { $result = null; $code($result); return $result; } // Wrap some code to make it compatible with the typehint. // In this case, we used a closure, but you may use anything // that is callable by PHP's standards (eg. a function, a method, // an anonymous function or an invokable object would be fine too) $wrapped = Erebot\CallableWrapper::wrap( function (&$retval) { $retval = 42; } ); // Outputs "int(42)" because the $result from invokeCode() // was by reference to the wrapped closure and modified there. var_dump(invokeCode($wrapped)); ?>
How it works
This is really a two-part process.
Under the hood, the wrapper's initialize
method first checks whether
it is running on PHP 5.3.x or not.
If it is, then Erebot\\CallableInterface
gets aliased as callable
in every currently-defined namespace. It also defines an autoloader
which is in charge of defining that class on the fly in the current namespace
when required. This is necessary for code such as the following where
callable
is used as a variable rather than directly as a typehint:
<?php $baseClass = "callable"; if ($objClass instanceof $baseClass) { // ... } ?>
Since the callable
typehint is only an alias to an interface, this is
why you need to wrap your code using the wrap
method provided,
to convert your callable code into an object compatible with that interface.
This is where the magic of the wrapper's wrap
method comes in.
It checks whether the given code is actually callable and then identifies
that code's signature (names of its arguments, which ones have default values,
which ones are passed by reference etc.) It then creates a new class
on the fly that implements the Erebot\\CallableInterface
interface
by defining an __invoke
magic method with that same signature.
To speed things up a little and to avoid using too much memory, the wrap
method uses a cache, where only a single class is ever created for the same
code signature.
Hence, code which relies on this wrapper works the same way both on PHP 5.3.x and on later versions.
License
Erebot's Callable component is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Erebot's Callable component is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with Erebot's Callable component. If not, see <http://www.gnu.org/licenses/>.