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JESS ®, the Rule Engine for the JavaTM Platform

Jess Demo

Here Jess is running a program that plays a simple game called Sticks. There is a pile of sticks, and players take turns removing one, two, or three sticks at each turn. The loser is the player forced to take the last stick. If you answer 'n' to 'Play again? (y/n)', you end up at the Jess command-line prompt, so you can experiment with Jess on your own. For example, you can do arithmetic in prefix notation like this: (+ (* 2 3) 3), which evaluates to 9.

  • This demo requires JavaScript.
  • To get help from the Jess> prompt, type "(help)". To see a list of available functions, type "(list-function$)".
  • To return to the game after leaving it, type "(reset)" and then "(run)".
  • This demo does not include the full Jess function set; many functions are disabled for security reasons.
  • Jess is a programmer's library. It comes with a command-line interface and sample console-style GUIs. You can write your own GUI for Jess in Java to suit your own applications; or you can write a GUI in the Jess language, or you can embed Jess in a larger application.
  • Most applications use Jess behind the scenes, not via an interactive prompt.
The rules for the sticks game.