{35}

Vassal works with whole numbers. It stores decimal numbers as strings.

{"German"}

A String literal, or text message, must be enclosed in "" quotation marks

/* Check not flipped */

Comments can be included in-line in an expression in any break between elements. .e.g.

{AmmoAP > 0 /* Check AP Ammo */}

Adding comments to expression does not affect performance in any way.

{Nation}
{LocationName}
{CurrentMap}
{playerName}

VASSAL interprets any word not enclosed in "" as a Property name.

Can refer by name to Global Properties, Marker and Dynamic Properties of pieces, and properties exposed by traits. The current value of the property will be used.

{"$Nation$"}
{$Attack$}

Property names enclosed by $..$ symbols immediately substitute the property value, based on the piece or component issuing the command.

Should only be used in Property Match Expressions to use properties from the issuing piece rather than target piece.

{(CurrentHP + 2) * (Damage - Resistance)}
{FirstName + "-" + Surname}
{Height * 10}
{width / 5}
{Level % 10}

Using the + operator on two String will concatenate (join) them. If the values on both sides of the + look like whole numbers, Vassal will attempt to add them.

Parentheses can be used to organize operations and/or override the ordinary order of operations.

{height > 10 }
{width < Level}
{Total >= HitPoints}
{breadth <= maxbreadth}
{Nation == "Germany"}
{Army != "Allied"}
{Type =~ "A|B|C}
{Type !~ "A|B|C}

Comparison operators come in handy for Property Match Expressions and also with the ? (ternary) operator.

Parentheses can be used to organize operations and/or override the ordinary order of operations.

For more examples and information about Regular Expressions see the dedicated RE page.

{Nation=="Germany" && Type == "Unit"}
{Nation == "Germany" || Type == "Unit"}
{Nation == "Germany" && Type == "Unit"}
{!isInUse}
{A==B && (C == 1 || D == 2)}

Comparison operators are used primarily in Property Match Expressions and also in the If function.

{ (Nation=="Germany") ? "Axis" : "Allies" }
{ (Nation == "Germany") ? 5 : 2 }
{ States.contains(CurrentZone) ? 1 : 0 }
{ IsRandom() ? "Heads" : "Tails" }
{A == B ? C : D}

The Ternary or "?" operator can be thought of as posing a yes/no question: if the expression before the ? symbol evaluates as "true", then the value of the expression as a whole is equal to the middle ("if true") part of the expression; otherwise (initial part is false), the result is the right ("if false") side.

{Math.abs(Number - 5)}
{Math.min(Health, Armor)}
{Math.max(3, Random(6))}

Math.abs() Returns the absolute value of the numeric property value1.

Math.min() Returns the smaller of two numeric values.

Math.max() Returns the larger of two numeric values.

{GetProperty("Nation"+myNation)}
{GetString("HowManyDogs")}
{GetAttachProperty("MyCrewMembers", "Health", 2)
{GetAttachProperty("MyCrewMembers", "Health", "Unit2")
{GetAttachProperty("MyCrewMembers", "Health", "{Str > 0}")
{GetMapProperty("Owner",CurrentMap)}
{GetZoneProperty("Militia","Georgia")}
{GetZoneProperty("Modifier",OldZone,OldMap)}

All GetProperty() family functions return the value of a named property. The name of the property can be constructed from an expression.

See the Property Functions page for full details.

{Random(6)}
{Random(AttackPower,AttackPower * 2)}
{IsRandom()}
{IsRandom(75)}

Random(value1) returns a random number between 1 and value1.

Random(value1,value2) returns a random number between value1 and value2.

IsRandom() returns "true" 50% of the time.

IsRandom(percent) returns "true" the specified percent of the time.

{ LocationName.length() }
{ States.contains("Arkansas") }
{ CurrentMap.isEmpty() } { OwnerString.startsWith("Axis") }
{ MaybeQuestion.endsWith("?") }
{ String.matches("[^abc]") }
{ WhereIsTheColon.indexOf(":") }
{ MaybeLotsOfDivs.lastIndexOf("div") }
{ CurrentZone.substring(5) }
{ PlayerName.substring(1,5) }
{ GetProperty("XX").replace("A","YY") }
{ Name.trim() }
{ Name.toUpperCase() }
{ Name.toLowerCase() }
{ AttackValue.toString() }

See the String Function page for examples and more information about String Functions.

{SumStack("Attack")}
{CountStack("Russian")}

{SumMat("AttackFactor")}
{CountMat("Followers")}

{SumAttach("MyMinions", "Ammo")}
{CountAttach("MyMinions", "{ Ammo > 0 }")}
{MaxAttach("MyMinions", "Strength")}
{MinAttach("MyMinions", "Health")}

{SumLocation("Strength")}
{CountLocation("Strength", "ReinforcementPool", "MainMap")}

{SumZone("Strength")}
{CountZone("Zone1", "Map2", "{Size > 2}")

{Sum("Strength", "{Owner=\"me\"}"}
{Count("{Owner=\"me\"}"}

There is an extensive range of Sum and Count functions to count pieces and to sum properties attached to pieces. See the Sum and Count Functions page for more details on choosing and using these Functions.

Range(0, 0)
RangePx(oldX, oldY)
Range("MyAttachment")
RangePx("Attack")
Range(0, 0, gp_x, gp_y)
RangePx(oldX, oldY, newX, newY)
Range(0, 0, gp_x, gp_y, "Main")
RangePx(oldX, oldY, newX, newY, "Battle")

Range functions calculate the range in pixels, or in grid units (hexes, squares) between 2 locations. See the Range Functions page for more details on choosing and using these Functions.

{Alert("Adding 1 to HP")}

Alert displays a message in a popup dialog box, to the currently active player only. If a message needs to be shown to all players, the recommended method is to send something to the Chat Log, e.g., with a Report Action trait or other Message Format field.