_{Official ZPE/YASS documentation}copy_of

Prior to the introduction of this, ZPETypes such as the ZPEFunction, ZPEList, ZPEAssociativeArray, ZPEString and ZPEObject data types could not directly be copied. Since ZPE uses by reference when using variable assignment changes made to one ZPEType affect any other instances of it.

$x = [11, 22, 33]
$y = $x
$y[1] = 44

//Will print [11, 44, 33]
print($x)