Optionals.php

<?php

// Okay, here's something I really like from Kotlin & Swift, they're called Optionals (or Nullable)
// var coolThing: Bool?
// this means that that variable may be one of three values, null, true, or false.

// PHP has had this forever you might say
// $cool_thing = null
// That var could become a string, int, bool, whatever you'd like! But here lies the intersection where
// the typed world can help PHP, I think.

if (!is_null($cool_thing)) {
  $cool_thing->doSomethingAwesome();
}

// Writing statements like the above is okay the first few thousand times you do it. In Kotlin / Swift you can
// do that without even noticing it like this:
// coolThing?.doSomethingAwesome();
// Let's see how close we can get to that in PHP...

// Initially I thought of using a function:
function ifLet($variable, $callback) {
  if (!is_null($variable)) {
    $callback($variable);
  }
}

// That's not too bad:
class Main {

  /**
   * @var string
   */
  protected $option;

  public function __construct($args) {
    if (isset($args['option'])) {
      ifLet($args['option'], function($option) {
        $this->option = $option;
      });
    }
  }
}

// That's not too bad! But older PHP devs will recognize that in a heartbeat as:
if ($option = $args['option']) {
  // do stuff...
}
// That's been done before! We want to see how else we can bend the language.

// Maybe we could use anon objects?
class Q {

  public $value = null;

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

  public function __call($name, $arguments) {
    if (!is_null($this->value) && method_exists($this->value, $name)) {
      call_user_func_array([$this->value, $name], $arguments);
    }
  }
}

class Person {
  public function name() {
    return "Fry";
  }
}

$not_fry = null;
$fry = new Person();

print( (new Q($not_fry))->name() );

// To be continued...