A constant is an identifier with a predefined value. Contrary to a variable the value of the constant can not be changed in run-time. During compilation the constant name is replaced with the value associated with it. The constant values can be numeric (numerals) and string (string literals), and contain an expression.

Syntax

To define a new constant use the CONST..END construct:

CONST <constant name> = <constant value> END

A constant name is any allowed identifier (a combination of letters, numbers and _). There are names reserved by the compiler that can not be used, such as Continue, Break, And, etc (see compiler.ini). A constant value might be a number (also a model identifier or a label); a string literal; a variable (also a class property); another constant.

const
    MoneyRequired = 30
    PlayerMoney = $PLAYER_CHAR.Money
end
​
if
    PlayerMoney > MoneyRequired
then
    PlayerMoney += -1
end

During compilation the constant MoneyRequired gets replaced with the number 30 and PlayerMoney with $PLAYER_CHAR.Money

​Edit modes can load constants from an external file by using the <constants> parameter in the games.xml.

A list of the currently defined constants is displayed after pressing Ctrl+Space.

Limitations

You can use constants anywhere except the case:

const
    VarName = $Var
    IndexName = 25
end
VarName[IndexName] = 0

To compile such expression, you must write the opcode, for example:

0004: VarName[IndexName] = 0

Also there are some limitations with using an expression as the constant value.