A singleton class loader. Will convert static calls to nonstatic calls and construct the class only when needed. Use this with caution, as it may make your code less readable.

example.php

<?php

# before
DB::getInstance()->query('sql');

# after
DB::query('sql');

# Notice: All functions in the extended class must be protected.

loader.php

<?php

class singletonConstructor {

	private function __construct(){}

	private static $children = [];

	private static function init($class){

		if(!isset(self::$children[$class])){

			self::$children[$class] = new $class;

		}

	}

	private static function call($name, $args){

		$class = get_called_class();

		self::init($class);

		if(!method_exists($class, $name)){

			throw new Error('Method ' . $name . ' does not exist in ' . $class);

		}

		return (self::$children[$class])->$name(...$args);

	}

	public function __call($name, $args){

		return self::call($name, $args);

	}

	public static function __callStatic($name, $args){

		return self::call($name, $args);

	}

	public static function _exists($class){

		return isset(self::$children[$class]);

	}

}