foo.clj

(use 'clojure.core.logic)

(defne all-in [x mems]
  ([[?a . ?b] mems]
    (membero ?a mems)
    (all-in ?b mems))
  ([() _]))

(defrel cocktail n)
(fact cocktail :martini)
(fact cocktail :martinez)
(fact cocktail :manhattan)
(fact cocktail :ginmule)

(defrel ingredient i)
(fact ingredient :a)
(fact ingredient :b)
(fact ingredient :c)
(fact ingredient :d)


(defrel ingredients n i)
(fact ingredients :martini [:a :b])
(fact ingredients :martinez [:a :b :c])
(fact ingredients :manhattan [:b :d])
(fact ingredients :ginmule [:c :b])

(run* [q]
  (fresh [a b c x y z r s t]
    (!= a b)
    (!= b c)
    (!= a c)
    (!= x y)
    (!= y z)
    (!= x z)
    (cocktail a)
    (cocktail b)
    (cocktail c)
    (ingredients a r)
    (ingredients b s)
    (ingredients c t)
    (all-in r [x y z])
    (all-in s [x y z])
    (all-in t [x y z])
    (ingredient x)
    (ingredient y)
    (ingredient z)
    (== q [a b c])))