core.clj

(defn game-n
  [N A & game-elements]
  {:pre [every? true? (map unique? A)]}
  (let [payoffs (payoff-matrix N A game-elements)]
    {:players (range N)
     :actions A
     :payoffs payoffs
     :utility-fn (fn utility-fn
                   ([actions]
                      {:pre [(= N (count actions))]}
                      (let [indices (map #(.indexOf %1 %2) A actions)]
                        (apply (partial mget payoffs) indices)))
                   ([actions player]
                      {:pre [(= N (count actions))
                             (<= player N)]}
                      (nth player (utility-fn actions))))}))

gistfile1.clj

game-theory.core> (def pd
                    (game-n 2
                            [[:confess :deny]
                             [:confess :deny]]

                            [[:confess :confess] [1, 1]]
                            [[:confess :deny]    [4, 0]]
                            [[:deny :confess]    [0, 4]]
                            [[:deny :deny]       [3, 3]]))
                            
#'game-theory.core/pd
game-theory.core> (:utility-fn pd [:confess :confess])
#<core$game_n$utility_fn__39171 game_theory.core$game_n$utility_fn__39171@1104203>
game-theory.core> (*1 [:confess :confess])
[1 1]
game-theory.core>