VASSAL Reference Manual

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Properties

A Property is like a variable in programming: it has a value which can be referenced by including its name in Expressions, Message Formats and other similar fields. Most types of Property have their values change through the course of the game. Some Properties can have their values set by commands provided in Game Pieces themselves; others have their values set by the system and cannot be changed from within the module.

Each Game Piece has its own set of properties (each with a name and a value) that can be used for identification by various components. You can add your own new properties to a Game Piece explicitly by adding Dynamic Property traits to create values which can be changed during the course of the game and Marker traits for properties whose values will remain constant. System-defined properties are also added implicitly when other traits are added (see below). Global Properties can also be defined for a Zone, a Map or for the entire module. If a referenced Property name is not defined in a Game Piece, the VASSAL looks for the value in the Zone containing the piece, then in the Map containing the piece, then in the module.

Properties can be matched using Expressions like name == value for an exact match, name != value for a non-match, or name =~ value for a regular expression match. For properties that return a numeric value (e.g. the level in a Layer) you can use <, <=, >, and >=. You can combine expressions using && for logical AND and || for a logical OR.

Components that use properties

Any Message Format defined in a Game Piece will substitute values for the properties defined on that Game Piece.
The Global Key Command component uses properties to determine which pieces will respond to the command.
The Game Piece Layers component uses properties to determine relative ordering when drawing pieces on the map.
The Trigger Action trait uses properties to determine when to fire a Key Command or Named Key Command .
The Text Label trait substitutes properties when setting the text of the label.
A Zone uses properties to specify a Zone Highlighter.

Properties defined by Game Pieces

The Basic Piece defines properties related to a piece's name, location, side, and whether it's selected.
The Layer trait defines properties related to the state of that Layer.
The Rotate trait defines properties related to the current facing of the piece.
The Text Label trait returns the value of the label as a property.
The Marker trait allows you to define your own static properties.
The Dynamic Property trait allows you to define your own changeable properties.
The Mark When Moved trait sets a property when a piece has moved.
The Mask trait sets a property when the piece is masked.
The Invisible trait sets a property when the piece is invisible.
The Property Sheet trait exposes a set of user-editable properties.

Properties defined by other components

The Global Property component defines properties for a Zone, Map or the module.
The Global Options component allows you to tie property values to preferences settings.
The results of a roll by a Dice Button is exposed as a property
A Deck component exposes the number of cards remaining as a Map-level property.

Handy Combined List of VASSAL-defined Properties for Game Pieces
Property	Trait	Description
BasicName	Basic Piece	The basic name of the piece.
ClickedX	Basic Piece	Map X-coordinate where player last right-clicked on piece to bring up context menu (or 0 if never).
ClickedY	Basic Piece	Map Y-coordinate where player last right-clicked on piece to bring up context menu (or 0 if never).
CurrentBoard	Basic Piece	Current Board name or "" if not on a map.
CurrentMap	Basic Piece	Current Map name or "" if not on a map.
CurrentX	Basic Piece	Current X-coordinate of the piece.
CurrentY	Basic Piece	Current Y-coordinate of the piece.
CurrentZone	Basic Piece	Current Zone name if the current map has a multi-zoned grid, or "" if the piece is not in any zone, or not on a map.
DeckName	Basic Piece	Current Deck name if stacked in a Deck, or "" if not in a Deck.
IgnoreGrid	Does not stack	"true" if this piece ignores the map grid when moving.
Immobile	Does not stack	"true" if this piece cannot be moved by drag and drop.
Invisible	Invisible	"true" if this piece is invisible to the current player.
InvisibleToOthers	Invisible	"true" if this piece is invisible to other players.
LocationName	Basic Piece	Name of the piece's current location, as determined by the map's Zone (if any) and grid settings.
Moved	Mark When Moved	"true" if this piece has moved since the last time its movement history was cleared.
NoStack	Does not stack	"true" if this piece cannot stack with other pieces.
Obscured	Mask	"true" if this piece is masked from the current player.
ObscuredToOthers	Mask	"true" if this piece is masked from other players.
OldBoard	Basic Piece	Board name prior to most recent movement.
OldLocationName	Basic Piece	Location name prior to most recent movement.
OldMap	Basic Piece	Map name prior to most recent movement.
OldX	Basic Piece	X coordinate prior to most recent movement.
OldY	Basic Piece	Y coordinate prior to most recent movement.
OldZone	Basic Piece	Zone name prior to most recent movement.
PieceName	Basic Piece	Full piece name including both Basic Name and all additional strings provided by traits.
playerSide	Basic Piece	Side of the current player (not the side of the piece).
Restricted	Restricted Access	"true" if there are restrictions as to who can access this piece.
Selected	Basic Piece	"true" if the piece is currently selected.
*<property_name>*	PropertySheet	The value of each property on the Property Sheet can be accessed via the property name.
<layername>_Active	Layer	"true" if the Layer <layername> is currently active.
<layername>_Image	Layer	The image name of the currently active layer for Layer <layername>.
<layername>_Level	Layer	The level number of the currently active layer for Layer <layername>.
<layername>_Name	Layer	The level name of the currently active layer for Layer <layername>.
<rotatename>_Facing	Can Rotate	The current facing number (1, 2, etc) for the Can Rotate trait <rotatename>.
<rotatename>_Degrees	Can Rotate	The current degrees of rotation for the Can Rotate trait <name>.
*<Property Name>*	Text Label	If the "Property Name" field in the trait is filled out, then a property with that name will be filled with the current value of the Text Label trait's Text field.
<deckname>_numPieces	Deck (Map level property)	Number of pieces/"cards" in the Deck <deckname>.
<deckname>_<expression_name>	Deck (Map level property)	The number of pieces/"cards" for which the named expression evaluates to true in the Deck <deckname>.

VASSAL Reference Manual

Properties

Handy Combined List of VASSAL-defined Properties for Game Pieces