PHP, Null Coalescing Operator

Earlier this month PHP 7.0.0 Alpha 1 was released. One item on the feature list caught my eye:

The null coalescing operator (??)

The background is at https://wiki.php.net/rfc/isset_ternary. In short it “returns the result of its first operand if it exists and is not NULL, or else its second operand”. It does this without triggering E_NOTICE.

A short example:

[sourcecode lang=”php”]
$action = $_GET[‘action’] ?? ‘none’;

// The same as: $action = isset($_GET[‘action’]) ? $_GET[‘action’] : ‘none’;
[/sourcecode]

I’m happy to see this make it into PHP 7.

First warning though, it may not always work the way you would expect it to. Specifically, $action = null ?? 'none'; results in $action being 'none'. But $action = false ?? 'none'; results in $action being false.

Second warning is that HHVM does not currently support the ?? operator. HHVM issue 4166 brings that up, but the last comment is from November 2014.