When working with a pointer to a collection, to call a class function on the pointer, the dereferenced pointer must be enclosed by parentheses. For example, suppose there is a collection of integers:

$myColl:=New collection(4; 712; 55)

and a pointer to that collection:

$ptr:=->$myColl

To get the size (.length) and maximum value (.max) of the collection from the pointer, make sure that the dereferenced pointer is surrounded by parentheses:

$size:=($ptr->).length // 3 $maxValue:=($ptr->).max() // 712