clojure if_clojure require_clojure入门(6)

感觉好多了! 现在我们来创建一个命令来收集游戏里的物品

(defn pickup-object [object]
  (cond (is-at? object location object-locations)
        (do
          (def object-locations (assoc object-locations object 'body))
          `(you are now carrying the ~object))
        :else '(you cannot get that.)))

这个函数检查物品是否在当前地点的地上-如果在,则将它放到list里面,并返回成功提示!否则提示失败! 现在我们来创建另一个SPEL来简化这条命令:

(defspel pickup [object] `(spel-print (pickup-object '~object)))

调用

(pickup whiskey-bottle)

user=> (pickup whiskey-bottle)
(you are now carrying the whiskey-bottle)

现在我们来添加更多有用的命令-首先,一个能让我们查看我们捡到的物品的函 数:

(defn inventory []
  (filter (fn [x] (is-at? x 'body object-locations)) objects))

以及一个检查我们是否有某个物品的函数:

(defn have? [object]
   (some #{object} (inventory)))

现在我们只剩下一件事情需要做了:添加一些特殊动作,使得玩家能够赢得游戏.第一条命令是让玩家在阁楼里给水桶焊接链条.

(def chain-welded false)

(defn weld [subject object]
  (cond (and (= location 'attic)
             (= subject 'chain)
             (= object 'bucket)
             (have? 'chain)
             (have? 'bucket)
             (not chain-welded))
        (do (def chain-welded true)
            '(the chain is now securely welded to the bucket -))
        :else '(you cannot weld like that -)))

首先我们创建了一个新的全局变量来进行判断,我们是否进行了此操作.然后我们创建了一个weld函数,来确认此操作的条件是否完成,如果已完成则进行此操作.

来试一下:

(weld 'chain 'bucket)

user=> (weld 'chain 'bucket)
(you cannot weld like that -)

Oops...我们没有水桶,也没有链条,是吧?周围也没有焊接的机器!

现在,让我们创建一条命令来将链条和水桶放到井里:

(def bucket-filled false)

(defn dunk [subject object]
  (cond (and (= location 'garden)
             (= subject 'bucket)
             (= object 'well)
             (have? 'bucket)
             chain-welded)
        (do (def bucket-filled true)
            '(the bucket is now full of water))
        :else '(you cannot dunk like that -)))

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