PHP equivalent for Ruby's or-equals (foo ||=bar)?

Question

In PHP I often write lines like

isset($foo)? NULL : $foo = 'bar'

In ruby there is a brilliant shortcut for that, called or equals

foo ||= 'bar'

Does PHP have such an operator, shortcut or method call? I cannot find one, but I might have missed it.

Answer 1

As of PHP 5.3 it's possible to use $foo ?: 'bar' Unless you expect $foo to be false

[edit]

Forget it. It still raises E_NOTICE if $foo is no set.

Answer 2

No, PHP does not have an equivalent for this.

On a sidenote, the example you give with the ternary operator should really read:

$foo = isset($foo) ? $foo : 'bar';

A ternary operation is not a shorthand if/else control structure, but it should be used to select between two expressions depending on a third one, rather than to select two sentences or paths of execution

Answer 3

No. According to w3schools, that operator doesn't exist.

Also, the PHP code you posted is rather cryptic. I prefer something like this:

if (!isset($foo)) $foo = 'bar';

Answer 4

From the manual:

Since PHP 5.3, it is possible to leave out the middle part of the ternary operator. Expression expr1 ?: expr3 returns expr1 if expr1 evaluates to TRUE, and expr3 otherwise.

It's not exactly the same though. Hope it helps anyway.

Answer 5

You could create your own function:

function setIfNotSet(&$var, $value) {
    if(!isset($var)) {
        $var = $value;
    }
}