syndicate-2017/racket/syndicate/examples/actor/forward-chaining-mini.rkt

18 lines
584 B
Racket

#lang syndicate
;; Minimal syndicate/actor variation on examples/forward-chaining.rkt.
(spawn (assert `(parent john douglas)))
(spawn (assert `(parent bob john)))
(spawn (assert `(parent ebbon bob)))
;; This looks like an implication:
;; (parent A C) ⇒ ((ancestor A C) ∧ ((ancestor C B) ⇒ (ancestor A B)))
;;
(spawn (during `(parent ,$A ,$C)
(assert `(ancestor ,A ,C))
(during `(ancestor ,C ,$B)
(assert `(ancestor ,A ,B)))))
(spawn (on (asserted `(ancestor ,$A ,$B))
(log-info "~a is an ancestor of ~a" A B)))