[messages] [Module Design] Check which boards are in the game

PunTheHun vassal at flyhi.de
Tue Feb 21 09:25:51 CET 2017

Hi all,
me again. Sorry if this has been asked before, but for all questions I
could think of, the forum replied "too common search words".

My map my have up to 3 boards: western (optional), main (mandatory),
eastern (optional); the optional/mandatory is real-life logic, not a
logic to be applied within VASSAL (just curious: could it be?). I want
to check which of the optional boards are in the game, with the aim of
automatically adding certain overlays.
I think I could place at-start-stacks on the optional boards, each with
a "dummy" piece that has the "set global property" trait; they would set
global properties I can access elsewhere (for example to calculate which
overlays show, if I implement the overlays as at-start pieces with a
(calculated) layer trait). However, this solution needs a command sent
to the pieces, or they will do nothing.
Is there a way to get the information without issuing a command? Or,
second best, a way to issue a command automatically when opening the
module (or a certain window)?

Other things I considered: Placing at-start pieces with certain global
properties on the optional maps; unfortunately I found no way to access
these zone-level global properties from a level "above" (e. g. module
level). Other ideas foundered because it seems that VASSAL stops
evaluating expressions when it encounters an error (?), such using for a
global property that has not been defined (tests seem to indicate that
it does not simply send back nothing, but stops evaluating, but I am by
no means sure about that).

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