Thats not tha much of a task.
Here is the trigger:
Event:
- a unit uses an item
Condition:
//if you would create your items, so that all bows(and only bows) are in one 'itemgroup' (like charged, permanent, campaign, ...) then the trigger would be one for all of them
- Itemclass of (item beeing manipulated) = <your bow class>
//otherwise if would be
- OR
- - Itemtype (Item beeing Manipulated) = bow 1
- - Itemtype (Item beeing Manipulated) = bow 2
- - Itemtype (Item beeing Manipulated) = bow x
Action:
- if
- condition
- - Player - Lumber of (Owner of (manipulating Unit)) > 0
- then
- - Player - Add '-1' to (Owner of (Manipulating Unit)) current Lumber
- else
- - order unit (manipulating unit) stop
that one should work, even though i'd do it different.
(no, i'll not say how i'd do it -> i don't have the time to write that stuff done right now -> if you want to now -> PM me and i might tell you)