Using a constant inside a static array

Question

Im on php 5.2.x

I have a loader class that looks like so:

class Loader {

    static $account_nameClasses = array(
        'DB' => '/home/account_name/public_html/includes/php/DB.php',
        'Skin' => '/home/account_name/public_html/includes/php/Skin.php',
        'API' => '/home/account_name/public_html/api/apiClass.php',
        'Search'  => '/home/account_name/public_html/includes/php/Search.php',
        'User'  => '/home/account_name/public_html/includes/php/User.php'
    );

    static function loader($className) {
        $filename = self::$account_nameClasses[$className];

        if(file_exists($filename)){
            require_once $filename;
        }else{
            return false;
        }
    }
}

spl_autoload_register(array(account_name_Loader, 'loader'));

As you can see, I repeat /home/account_name/public_html/includes/php/ over and over.

I want to replace that with a constant (or anything else) so that I can easily change it if I move the location of the app.

I tried this (Any may forms of this), but it just doesn't work

const PHP_CLASSES_ROOT = '/home/account_name/www/';

static $account_nameClasses = array(
    'DB' => self::PHP_CLASSES_ROOT.'DB.php',
    'Skin' => self::PHP_CLASSES_ROOT.'Skin.php',
    'Search'  => self::PHP_CLASSES_ROOT.'Search.php',
    'User'  => self::PHP_CLASSES_ROOT.'User.php'
);

Any ideas?

possible duplicate of [Attribute declarations in a class definition can only be constant values, not expressions.](http://stackoverflow.com/questions/2671928/workaround-for-basic-syntax-not-being-parsed) — mario, Jan 22 '12 at 23:04

score 2 · Accepted Answer · answered Jan 22 '12 at 23:02

You can modify the loader function:

class Loader {
    const PHP_CLASSES_ROOT = '/home/account_name/public_html/includes/php/';

    static $account_nameClasses = array(
        'DB' => 'DB.php',
        'Skin' => 'Skin.php',
        'API' => 'apiClass.php',
        'Search'  => 'Search.php',
        'User'  => 'User.php'
    );

    static function loader($className) {
        $filename = Loader::PHP_CLASSES_ROOT.self::$account_nameClasses[$className];

        if(file_exists($filename)){
            require_once $filename;
        }else{
            return false;
        }
    }
}

spl_autoload_register(array(account_name_Loader, 'loader'));

Of if the class names are used elsewhere you can create a function to build paths:

class Loader {
    const PHP_CLASSES_ROOT = '/home/account_name/public_html/includes/php/';

    static $account_nameClasses = array(
        'DB' => 'DB.php',
        'Skin' => 'Skin.php',
        'API' => 'apiClass.php',
        'Search'  => 'Search.php',
        'User'  => 'User.php'
    );

    static function resolveClassPath($className) {
        return Loader::PHP_CLASSES_ROOT . $filename;
    }

    static function loader($className) {
        $filename = self::resolveClassPath($className);

        if(file_exists($filename)){
            require_once $filename;
        }else{
            return false;
        }
    }
}

spl_autoload_register(array(account_name_Loader, 'loader'));

score 0 · Answer 2 · answered Jan 22 '12 at 23:03

0

You can change your loader function to prepend this constant to $filename

static function loader($className) {
    $filename = self::PHP_CLASSES_ROOT . self::$account_nameClasses[$className];
    /* ... */
}

answered Jan 22 '12 at 23:03

dev-null-dweller

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Matt Lo · Answer 3 · 2012-01-22T23:13:51.500

When you call a static property, it's already assigned but has no idea PHP_CLASSES_ROOT exists because its a property (cannot be invoked) and not a method.

class Loader {

   const PHP_CLASSES_ROOT = '/home/bildr/www/';

   static public function account_nameClasses() {
      return array(
         'DB' => self::PHP_CLASSES_ROOT.'DB.php',
         'Skin' => self::PHP_CLASSES_ROOT.'Skin.php',
         'Search'  => self::PHP_CLASSES_ROOT.'Search.php',
         'User'  => self::PHP_CLASSES_ROOT.'User.php'
      );
   }

   //...

}

print_r(Loader::account_nameClasses());

Using a constant inside a static array

3 Answers3