tictactoe.clj

(defn solve
  [grid]
  (remove nil?
          (run* [q]
            (macro/symbol-macrolet [_ (lvar)]
              (== q grid)
              (conde
                ((== grid [[q _ _]
                           [_ q _]
                           [_ _ q]]))
                ((== grid [[_ _ q]
                           [_ q _]
                           [q _ _]]))

                ((== grid [[q _ _]
                           [q _ _]
                           [q _ _]]))
                ((== grid [[_ q _]
                           [_ q _]
                           [_ q _]]))
                ((== grid [[_ _ q]
                           [_ _ q]
                           [_ _ q]]))

                ((== grid [[q q q]
                           [_ _ _]
                           [_ _ _]]))
                ((== grid [[_ _ _]
                           [q q q]
                           [_ _ _]]))
                ((== grid [[_ _ _]
                           [_ _ _]
                           [q q q]])))))))

(solve [[:y  :x :y]
        [nil :x nil]
        [nil :x nil]])
; => (:x)