https://www.microfocus.com/documentation/silk-test/200/en/silktestclassic-help-en/STCLASSIC-55CE7EEF-INCREMENTANDDECREMENTOPERATORS-REF.html
The ++ (increment) and -- (decrement) operators take a single argument.
decrement operatorsincrement
https://www.microfocus.com/documentation/silk-performer/200/ja/silkperformer-200-webhelp-ja/GUID-5DB2FB37-6521-4B5C-9BA3-577F1F05805F.html
Describes the increment (--) and decrement (++) operators, which are supported for number varibles.
decrement operatorsincrement