```
(defn interpereter [expr env]
(if (list? expr)
(let [[p1 p2 p3 p4] expr]
(match [p1 p2 p3 p4]

['if pred true-branch false-branch ]
(if (interpereter pred env)
(interpereter true-branch env)
(interpereter false-branch env))

['* arg1 arg2 nil]
(* (interpereter arg1 env) (interpereter arg2 env))

['dec arg nil nil]
(dec (interpereter arg env) )

['zero? param nil nil]
(zero? (interpereter param env))

[func params nil nil]
((interpereter func env) (interpereter params env))

['fn [x] body nil]
(fn [arg]
(interpereter body (fn [y]
(if (= x y)
arg
(env y)))))

:else (assert false (str "未能捕获 list:" expr))))
(match [expr]
[(n :guard symbol?)] (env n)
[(n :guard number?)] n
:else (assert false (str "未能捕获元素:" expr)))))

(interpereter '(((fn [!]
(fn [n]
((! !) n)))
(fn [!]
(fn [n]
(if (zero? n)
1
(* n ((! !) (dec n)))))))
5)
(fn [e] (assert false (str "no such element.." e) )))
```