Does anyone know if the following expression will be possible in the next version(s) of PHP?
(new A())->a(); // Causes a syntax error
I find very annoying that currently one must write 2 lines instead of 1:
$c = new A();
$c->a();
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possible duplicate of [How to chain method on a newly created object?](http://stackoverflow.com/questions/2188629/how-to-chain-method-on-a-newly-created-object) – artfulrobot Jan 28 '15 at 09:52
3 Answers
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The first version does not cause a parse error, it is perfectly valid. The second it is, indeed not possible, but you can easily overcome such a problem with some coding standards.
If every team member creates, for each defined class, a function with the same name as the class, and a signature similar to the signature of the class constructor, then you won't have the second problem. Example:
class Foo
{
public function __construct($param)
{}
public function bar()
{}
}
/**
* @return Foo
*/
function Foo($param)
{
return new Foo($param);
}
Foo()->bar();
Of course, you'll still have problems with library code.
Ionuț G. Stan
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Right, the first one is non-issue. I must have confused it with something else. I'll edit the question. Thanks – Ivan Krechetov Jan 27 '09 at 08:39
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I think you confused it with functionReturnsArray()[3], which is indeed not possible. There have been proposals, but they didn't get accepted. PHP internals don't like that shortcut. – Ionuț G. Stan Jan 27 '09 at 08:48
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Iount: do you have any links to the discussing regarding this? This is a feature I really miss :( – Jan Hančič Jan 27 '09 at 11:08
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http://markmail.org/message/kk2hwn3gdjcw2yfh#query:related%3Akk2hwn3gdjcw2yfh+page:1+mid:5bv6mtd7zorni7gc+state:results http://wiki.php.net/rfc/functionarraydereferencing – Ionuț G. Stan Jan 27 '09 at 11:23
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Can anyone tell me if this is a common idiom in PHP? Do people often do this,that is define a global fn that returns the object? – Aaron May 14 '10 at 00:45
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No, it's not a common idiom. I've seen it used by me and just one other person. – Ionuț G. Stan May 14 '10 at 21:33
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"The first version does not cause a parse error, it is perfectly valid." Wish Stack Overflow had visible revisions so I could see what you're talking about here before it was edited. EDIT: Found them! Just need to click on the date. <3 – mattalxndr Sep 10 '10 at 06:00
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A new-expression can be used as a function argument. A function call can be used as the left-hand side of the member access operator. Therefore, you just need to define a single function:
function with($object) { return $object; }
with(new A()) -> a();
No additional efforts required on a per-class basis.
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I like this, although it ends up being a bit weird if you also need a reference to the object for later use. Unless the method(s) you call return a reference to the object (e.g. are specifically chainable), then you need to do `with($my_object = new A())->a();`. But it's a novel way around a limitation, thanks! – artfulrobot Jan 28 '15 at 09:48
