In PHP, can you instantiate an object and call a method on the same line?

Question

What I would like to do is something like this:

$method_result = new Obj()->method();

Instead of having to do:

$obj = new Obj();
$method_result = $obj->method();

The result doesn't actually matter to me in my specific case. But, is there a way to do this?

Answer 1

The feature you have asked for is available from PHP 5.4. Here is the list of new features in PHP 5.4:

https://php-legacy-docs.zend.com/manual/php5/en/migration54.new-features

And the relevant part from the new features list:

Class member access on instantiation has been added, e.g. (new Foo)->bar().

Answer 2

You cannot do what you are asking ; but you can "cheat", using the fact that, in PHP, you can have a function that has the same name as a class ; those names won't conflict.

So, if you declared a class like this :

class Test {
    public function __construct($param) {
        $this->_var = $param;
    }
    public function myMethod() {
        return $this->_var * 2;
    }
    protected $_var;
}

You can then declare a function that returns an instance of that class -- and has exactly the same name as the class :

function Test($param) {
    return new Test($param);
}

And now, it becomes possible to use a one-liner, like you asked -- only thing is you are calling the function, thus not using new :

$a = Test(10)->myMethod();
var_dump($a);

And it works : here, I'm getting :

int 20

as output.

And, better, you can put some phpdoc on your function :

/**
 * @return Test
 */
function Test($param) {
    return new Test($param);
}

This way, you'll even have hints in your IDE -- at least, with Eclipse PDT 2.x ; see the screeshot :

---

Edit 2010-11-30 : Just for information, a new RFC has been submitted, a few days ago, that proposes to add this feature to one of the future versions of PHP.

See : Request for Comments: Instance and method call/property access

So, maybe doing things like these will be possible in PHP 5.4 or another future version :

(new foo())->bar()
(new $foo())->bar
(new $bar->y)->x
(new foo)[0]

Answer 3

How about:

$obj = new Obj(); $method_result = $obj->method(); // ?

:P

Answer 4

You can do it more universally by defining an identity function:

function identity($x) {
    return $x;
}

identity(new Obj)->method();

That way you don't need to define a function for each class.

Answer 5

No, this is not possible.
You need to assign the instance to a variable before you can call any of it's methods.

If you really wan't to do this you could use a factory as ropstah suggests:

class ObjFactory{
  public static function newObj(){
      return new Obj();
  }
}
ObjFactory::newObj()->method();

Answer 6

Simply we can do this

$method_result = (new Obj())->method();

Answer 7

You could use a static factory method to produce the object:

ObjectFactory::NewObj()->method();

Answer 8

I, too, was looking for a one-liner to accomplish this as part of a single expression for converting dates from one format to another. I like doing this in a single line of code because it is a single logical operation. So, this is a little cryptic, but it lets you instantiate and use a date object within a single line:

$newDateString = ($d = new DateTime('2011-08-30') ? $d->format('F d, Y') : '');

Another way to one-line the conversion of date strings from one format to another is to use a helper function to manage the OO parts of the code:

function convertDate($oldDateString,$newDateFormatString) {
    $d = new DateTime($oldDateString);
    return $d->format($newDateFormatString);
}

$myNewDate = convertDate($myOldDate,'F d, Y');

I think the object oriented approach is cool and necessary, but it can sometimes be tedious, requiring too many steps to accomplish simple operations.

Answer 9

I see this is quite old as questions go but here is something I think should be mentioned:

The special class method called "__call()" can be used to create new items inside of a class. You use it like this:

<?php
class test
{

function __call($func,$args)
{
    echo "I am here - $func\n";
}

}

    $a = new test();
    $a->new( "My new class" );
?>

Output should be:

I am here - new

Thus, you can fool PHP into making a "new" command inside of your top level class (or any class really) and put your include command in to the __call() function to include the class that you have asked for. Of course, you would probably want to test $func to make sure it is a "new" command that was sent to the __call() command and (of course) you could have other commands also because of how __call() works.

Answer 10

Additionally, you can also clone an object and call a method on the same line too:

(clone $image)->save('thumbnail.jpg');

I actually struggled find it out. I thought it could help some people.