Can’t use function return value in write context

PHP likes to give this error message when using function return values directly with the empty construct.

if (empty(some_function())
{
    // ... some code here
}

This is due to how empty is implemented in PHP.

The obvious solution is to store the value in a temporary variable first and then applying empty:

$value = some_function();
if (empty($value))
{
    // ... some code here
}

There is a shorter way, though.

Depending on whether you use empty or !empty, the shortest way to use the function return value directly is this:

// Replacing empty
if (!some_function())
{
    // ... some code here
}

// Replacing !empty
if ((bool) some_function())
{
    // ... some code here
}

This solution makes clever use of PHP's type casting to booleans - and keeps the code short.

NOTE: This not only works for arrays, but also for strings.