Use Default Property Values

It is possible to declare default values for properties.

<?php

class Dog {
	public $name = 'Rex';
	private $tatoo;
	
	public function __construct($tatoo, $name = null) {
		$this->tatoo = $tatoo; // only initialized with incoming data
		if ($name === null) {
			$this->name = $name; 
		} else {
			$this->name = 'Rex'; // May be omitted, as it is already the default value for name
		}
	}
}
?>

Default values are easier to find when they are set a declaration time, instead than in the middle of the code. This also means less code written in the constructor.

It is recommended to set default values to properties.

Rule Details

The following are considered warning :

<?php

class x {
	public $a; //
	public $b; //
	
	function __construct($c) {
		$this->a = 2;  // should be set in the declaration
		
		if ($c == true) {
			$this->b = $c;
		} else {
			$this->b = 'default value'; // should be set in the declaration
		}
	}
}

?>

The following are considered legit :

<?php

class x {
	public $d = 1; // d has a default value and is not set in constructor
	public $e; // e is set with a constructor argument
	public $f; // f is set with a constructor argument
	
	function __construct($c) {
		$this->e = $c;  // no special default value
		
		if ($c === 1) {
			$this->f = 'd'; 
		} elseif ($c === 2) {
			$this->f = 'e'; 
		} else {
			$this->f = $c;
		}
	}
}

?>