MTG: Arena uses a rules engine CLIPS (a s-expr expert system based on the RETE engine), which an acquaintance wrote a course for: https://ryjo.codes/tour-of-cli

MTG: Arena uses a rules engine CLIPS (a s-expr expert system based on the RETE engine), which an acquaintance wrote a course for: https://ryjo.codes/tour-of-clips.html https://ryjo.codes/tour-of-clips.html and even a declarative chat server: https://ryjo.codes/articles/a-simple-tcp-server-written-in-go-and-clips.html https://ryjo.codes/articles/a-simple-tcp-server-written-in-g... (defrule connection (connection ?id) => (println "User " ?id " connected") (printout ?id "Welcome to the chatroom from CLIPS!" crlf) (do-for-all-facts ((?f connection)) (neq ?id (nth$ 1 ?f:implied)) (printout (nth$ 1 ?f:implied) "User " ?id " connected" crlf))) (defrule say (connection ?id) ?f <- (message-buffered ?id) ?ff <- (message ?id ~/me ?message) => (retract ?f ?ff) (printout ?id "You: " ?message crlf) (do-for-all-facts ((?f connection)) (neq ?id (nth$ 1 ?f:implied)) (printout (nth$ 1 ?f:implied) ?id ": " ?message crlf)))