The internal plugin DiceExpressionPlugin provides a simple way to specify dice rolls.
The simplest dice rolling expression looks like this:
1.d
This script rolls one default die (a six-sided die). Obviously, you can roll any kind of dice you want:
5.d15 15.d20 2.d100 1.pd 1.'d%'
Except for the last two lines - which means the same thing (roll a percentile die) - the code is very easy to follow for those who know a bit about dice notation.
A useful feature is what we call dynamic dice, which allows you to dynamically specify the type of dice to roll. For example, imagine that your script needs to ask the user for the dice type:
def n = new Scanner(System.in).nextLine() 5.d(n) // 'n' is a number or a '%'
This feature also allows you to use another dice roll as argument to that method:
6.d(3.d4)
This script rolls three four-sided dice and then rolls six dice of that many sides.