calling class method (with constructors) without object instantiation in php

Unfortunately PHP doesn't have support to do this, but you are a creative and look guy :D

You can use an "factory", sample:

<?php

class Foo
{
   private $__aaa = null;

   public function __construct($aaa)
   {
      $this->__aaa = $aaa;
   }

   public static function factory($aaa)
   {
      return new Foo($aaa);
   }

   public function doX()
   {
      return $this->__aaa * 2;
   }
}

Foo::factory(10)->doX();   // outputs 20

Just do this (in PHP >= 5.4):

$t = (new Test("Hello"))->foo("world");

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.

You can't call an instance-level method without an instance. Your syntax:

echo Test("world")::alert("hello");

doesn't make a lot of sense. Either you're creating an inline instance and discarding it immediately or the alert() method has no implicit this instance.

Assuming:

class Test {
  public function __construct($message) {
    $this->message = $message;
  }

  public function foo($message) {
    echo "$this->message $message";
  }
}

you can do:

$t = new Test("Hello");
$t->foo("world");

but PHP syntax doesn't allow:

new Test("Hello")->foo("world");

which would otherwise be the equivalent. There are a few examples of this in PHP (eg using array indexing on a function return). That's just the way it is.

// this does not work:
echo Test("world")::alert("hello");

// works, as you are calling not to an object of the class, but to its namespace
echo Test::alert("hello");

For this you can do a

https://www.php.net/manual/en/reflectionclass.newinstancewithoutconstructor.php

reflect your class and trigger the new instance without constructor.

Here a sample code:

<?php

class Test {
    private $end="";

    function __construct($value) {
        $this->end=$value;
    }

    public function alert($value) {
        echo $value." ".$this->end;
    }

    public function end($value) {

        $this->end = $value;        

        return $this; // return Test object so that you can chain to other function method.
    }
}

// Solution #1:
// reflect your class.
$reflector = new \ReflectionClass('Test');

// Then create a new instance without Constructor.
// This will ignore the constructor BUT it will create a new instance of class Test.
$say = $reflector->newInstanceWithoutConstructor();

// use end method that will return the Test object, then you can chain the alert()
$say->end('World!')->alert("Hello"); // output: Hello World!

?>