Variables

A "variable" simulates the behavior of a in-game placeholder.

Programmatically, a variable is represented by the Variable(name, value) object.
getVariables() returns a mutable list of variables:

let variable = new Variable('%test%', 'abc');   // instantiating a variable
getVariables().add(variable);                   // adding
getVariable('%test%').setValue('def');          // getting a variable and setting its value
getVariables().remove(variable);                // removing