Methods for accessing PHP global variables

Question

$GLOBALS['current_view'] and global $current_view, which do you prefer and why?

Answer 1

Neither, pass parameters into the methods. Every time you use globals, God kills a kitten.

Answer 2

If I must use globals, and I avoid them like the plague, I use global $current_view. I just prefer to always have a locally scoped variable rather than relying on super globals. But I think its a matter of preference.

Answer 3

Personally, I prefer the $GLOBALS['glob'] syntax because I can just copy paste the code without having to worry about declaring variables as globals. Keep in mind that you should try to keep globals to a minimum (maybe just global configuration directives, and even there...).

However, the two methods are not exactly synonymous; there's a slight difference:

function func() {
    var_dump($GLOBALS['glob']);
}

function func2() {
    global $glob;
    var_dump($glob);
}

The first one will emit a notice if the global 'glob' does not exist. The second one won't.

In the first case, sending $GLOBALS['glob'] as an argument compiles to:

     3      FETCH_R                      global              $0      'GLOBALS'
     4      FETCH_DIM_R                                      $1      $0, 'glob'

You're fetching GLOBALS and its index glob in a read context; no variable is created.

The second one compiles to

     compiled vars:  !0 = $glob
     ...
     2      FETCH_W                      global lock         $0      'glob'
     3      ASSIGN_REF                                               !0, $0

You are creating a reference to the global glob, so it is implicitly created if it doesn't exist.

Also:

function func_unset() {
    unset($GLOBALS['glob']);
}

function func2_unset() {
    global $glob;
    unset($glob);
}

The function func() will actually unset the global, func2_unset will merely destroy the reference that was created.

Note that func2 is very similar to:

function func3() {
    $glob =& $GLOBALS['glob'];
}

This one is however potentially less efficient. It compiles to

     2      FETCH_W                      global              $0      'GLOBALS'
     3      FETCH_DIM_W                                      $1      $0, 'glob'
     4      ASSIGN_REF                                               !0, $1

Answer 4

static classes ftw

class View {
    private static $current = null;
    public static function get_current() {
        return self::$current;
    }
}