hard_rule.clj

(ns yvern.hard-rule
  (:require [clara.rules :refer [defrule insert!]]))

(def $ (comp val first))

(defrule all-together
  [?middle <- :middle]
  [:or
   [:and [?max <- :top] [?min <- :bottom]]
   [:and [?min <- :left] [?max <- :right]]]
  =>
  (cond
    (<= ($ ?max) ($ ?middle))
    (insert! {:fact-type :overflow})

    (<= ($ ?middle) ($ ?min))
    (insert! {:fact-type :underflow})))