Game Piece Inventory Question

Module Design
1

How do you write an expression to test for existence of a property?

I want to inventory all pieces on the current map (can do this part) that have a specific property defined, regardless of the actual value and want to NOT inventory pieces that don’t have the property defined.

Example: Marker = Nation (values could be US, Germany, Italy, etc.) So I want to inventory every piece with a Marker value defined…

The VASSAL Reference Manual - Beanshell Expressions hints at the possibility (e.g., !isInUse)…

I’m virtually sure there is a way to do this, but know know the correct syntax…

2

I rely on the property being null is undefined. Of course, that doesn’t help you if null is a valid value for the property itself.