Am 12.10.2012 23:06, schrieb Nikita Popov:
On Fri, Oct 12, 2012 at 10:58 AM, Christian Kaps
<christian.k...@mohiva.com> wrote:
At the moment it isn't possible to restrict/define the arguments for a
closure which is defined as parameter for a method. Please look at this
small example.
interface Broker {
public function scan(Request $request, Closure $onFound);
}
An implementation of the interface could be as follows:
class BrokerImpl implements Broker {
/**
* @var Service
*/
private $service = null;
public function scan(Request $request, Closure $onFound) {
if ($request->contains('some value')) {
$onFound($this->service);
}
}
}
The problem is that I can pass every closure to the scan method.
$broker = new BrokerImpl();
$broker->scan($request, function() { /* do something */ });
Sometimes I would like to restrict the closure passed to this method. So
that only closures of a certain type which has an argument "Service
$service" could be passed to this method.
$broker = new BrokerImpl();
$broker->scan($request, function(Service $service) { /* do something */ });
Would it not be possible to extend the Closure class and then define an
abstract method signature for the __invoke method.
class OnFoundClosure extends Closure {
public abstract function __invoke(Service $service);
}
And then you can define the interface as follows:
interface Broker {
public function scan(Request $request, OnFoundClosure $onFound);
}
Now if you pass a closure to the scan method which doesn't follow the
signature of the __invoke method, the engine should throw an error.
What do you think?
Please also don't forget that PHP doesn't have strict function
signatures. E.g. you can write
function($foo) {
echo $foo;
}
but you could also write
function() {
$foo = func_get_arg(0);
echo $foo;
}
So I'm not sure just how much sense function signature checking makes in PHP ;)
Nikita
What did you mean with strict function signatures?
Is this not a strict function signature?
function(Foo $foo) {}
Christian
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