_{Official ZPE/YASS documentation}Unset

The ZPE unset feature has been included as a YASS language keyword since ZPE 1.12.4. Prior to this it was a predefined function which can be found here.

unset destroys any references to a variable. It follows the standard variable hierarchy in that it will find a local variable, then a parameter then a global variable which if not found will result in the function returning false.

Using unset

The unset feature works like a function syntactically but it differs in it's implementation.

$a = 10
unset($a)
print($a)
$b = [11, 22, 33]
unset($b[2])
print($b)
        

Before becoming a keyword

Prior to unset becoming a language keyword, the unset was a function. Part of the design philosophy behind making a keyword was to make execution faster as it was a widely used function but whilst maintaining compatibility with existing scripts.

The unset function is one of the oldest functions in ZPE. You can read more about it here.