盒子
盒子
文章目录
  1. Lisp中的特殊数据结构
    1. Arrays
    2. Hash Table
      1. 返回多值
    3. Structures
    4. Generical Programming
  2. The Orc Battle Game

The Orc Battle Game

2012-05-03 | Liu Yuyang | lisp

Lisp中的特殊数据结构

引用原文中的话来形容Lisp,

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Think of the Babel fish in the Hitchhiker’s Guide to the Galaxy trilogy—something 
so impossibly useful that it really has no business existing in the first place.

现在知道land of lisp的作者为什么把common lisp比作狼狗，为什么说cl强大了。支持list也就算了，支持个array、hash table、OOp、范型(generic)什么乱七八糟一堆其它语言中各种强大的东西，这么逆天的东西根本就不该存在！不过作为代价，丧失了一种纯粹的美。

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lisp is symmetry,while common lisp is powerful.

Arrays

一些有用的命令

  • make-array
  • aref
  • setf

array有比列表更高的效率

Hash Table

这玩意强到逆天：

  • make-hash-table
  • gethash

返回多值

  • round
  • values
  • multiple-value-bind

hash表性能总体还是很高的..比如说我们上回写的wumpus游戏，我们可以分别对hash表和alists运行效率做如下对比。先看alists：

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(load "/home/lyy/Documents/lisp/wumpus.lisp")
(setf *edge-num* 1000)
(setf *node-num* 1000)
(time (dotimes (i 100) (get-connected 1 (make-edge-list))))

好吧，我花的时间：

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(time (dotimes (i 100) (get-connected 1 (make-edge-list))))
Real time: 64.1503 sec.
Run time: 64.025826 sec.
Space: 75275184 Bytes
GC: 65, GC time: 0.43664 sec.
NIL

下面我们更改之前的wumpus游戏。

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;;生成hash表的边版本
(defun hash-edges (edge-list)
  (let ((tab (make-hash-table)))
    (mapc (lambda (x);mapc返回副作用
            (let ((node (car x)))
              (push (cdr x) (gethash node tab))));推入新值
          edge-list)
    tab))
;;生成hash表。如果与node相连，则hash表中值为t
(defun get-connected-hash (node edge-tab)
  (let ((visited (make-hash-table)))
    (labels ((traverse (node)
               (unless (gethash node visited);非则执行
                 (setf (gethash node visited) t)
                 (mapc (lambda (edge)
                         (traverse edge))
                       (gethash node edge-tab)))))
      (traverse node))
    visited))
;;可以看看什么样的
;;看看运行时间
(time (dotimes (i 100)
        (get-connected-hash 1 (hash-edges (make-edge-list)))))

很显然，效率高多了：

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(time (dotimes (i 100)
        (get-connected-hash 1 (hash-edges (make-edge-list)))))
Real time: 1.530112 sec.
Run time: 1.526567 sec.
Space: 64337496 Bytes
GC: 56, GC time: 0.366641 sec.
NIL

Structures

构建structure可以直接用defstruct：

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(defstruct person
  name
  age
  waist-size
  favorite-color)
;;然后进行跟改
(defparameter *bob* (make-person :name "Bob";make-person函数自动生成
                                 :age 35
                                 :waist-size 32
                                 :favorite-color "blue"))
*bob* ;查看
;#S(person :name "rob" :age 35 :waist-size 32 :favorite-color "blue")
(person-age *bob*);自动生成person-age函数
(setf (person-age *bob*) 36);generical programming

也可以直接这样：

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(defparameter *that-guy* #S(person :name "rob" :age 35 :waist-size 32
                                   :favorite-color "blue"))
(print *that-guy*)

Generical Programming

有些范函可以接受多种类型参数,典型的sequence函数有：

  • length
  • sequence
  • find-if
  • count
  • position
  • some
  • every
  • reduce
  • subseq
  • sort

通过类型检验创建generic function是可行的但不太好。有种叫作type dispatching的东西可以让用户自己通过defmethod来定义generic function。

The Orc Battle Game

好了，之前全是扯淡。开始进入正题，写我们的新游戏：

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;;;player的三属性
(defparameter *player-health* nil)
(defparameter *player-agility* nil)
(defparameter *player-strength* nil)
;;;monsters
(defparameter *monsters* nil)
(defparameter *monster-builders* nil);各种怪物
(defparameter *monster-num* 12)
(princ *monster-builders*) 
;;;main function
(defun orc-battle ()
  (init-monsters)
  (init-player)
  (game-loop)
  (when (player-dead)
    (princ "You have been killed. Game Over."))
  (when (monsters-dead)
    (princ "Congratulations! You have vanquished all of your foes.")))
;;;define game loop
(defun game-loop ()
  (unless (or (player-dead) (monsters-dead))
    (show-player)
  ;;依据敏捷计算攻击次数
    (dotimes (k (1+ (truncate (/ (max 0 *player-agility*) 15))))
      (unless (monsters-dead)
        (show-monsters)
        (player-attack)))
    (fresh-line)
    (map 'list
         (lambda(m)
           (or (monster-dead m) (monster-attack m)))
         *monsters*)
    (game-loop)))
;;;manage players function
(defun init-player ()
  (setf *player-health* 30)
  (setf *player-agility* 30)
  (setf *player-strength* 30))
(defun player-dead ()
  (<= *player-health* 0))
(defun show-player ()
  (fresh-line)
  (princ "You are a valiant knight with a health of ")
  (princ *player-health*)
  (princ ", an agility of ")
  (princ *player-agility*)
  (princ ", and a strength of ")
  (princ *player-strength*))
(defun player-attack ()
  (fresh-line)
  (princ "Attack style: [s]tab [d]ouble swing [r]oundhouse:")
  (case (read);case函数
    (s (monster-hit (pick-monster);monster-hit表monster被攻击
                    (+ 2 (randval (ash *player-strength* -1)))))
    (d (let ((x (randval (truncate (/ *player-strength* 6)))))
         (princ "Your double swing has a strength of ")
         (princ x)
         (fresh-line)
         (monster-hit (pick-monster) x)
         (unless (monsters-dead);除非第一次攻击就消灭所有怪物
           (monster-hit (pick-monster) x))))
    (otherwise (dotimes (x (1+ (randval (truncate (/ *player-strength* 3)))))
;否则一阵乱打
                 (unless (monsters-dead);若之中有一次已经消灭所有怪物
                   (monster-hit (random-monster) 1))))))
;;;产生不小于1的1到n的随机数
(defun randval (n)
  (1+ (random (max 1 n))));以防n<1
;;;Player Attacks的辅助函数
;;随机活着的怪物编号
(defun random-monster ()
  (let ((m (aref *monsters* (random (length *monsters*)))))
    (if (monster-dead m)
      (random-monster)
      m)))

;;选择特定monster
(defun pick-monster ()
  (fresh-line)
  (princ "Monster #:")
  (let ((x (read)))
    (if (not (and (integerp x) (>= x 1) (<= x *monster-num*)))
      (progn (princ "That is not a valid monster number.")
             (pick-monster))
      (let ((m (aref *monsters* (1- x))))
        (if (monster-dead m)
          (progn (princ "That monster is alread dead.")
                 (pick-monster))
          m)))))
;;Monster Management Functions
(defun init-monsters ()
  (setf *monsters*
        (map 'vector
             (lambda (x);I make no sense of it
               (funcall (nth (random (length *monster-builders*))
                             *monster-builders*)))
             (make-array *monster-num*))))
(defun monster-dead (m)
  (<= (monster-health m) 0))
(defun monsters-dead ()
  (every #'monster-dead *monsters*))

(defun show-monsters ()
  (fresh-line)
  (princ "Your foes:")
  (let ((x 0))
    (map 'list
         (lambda (m)
           (fresh-line)
           (princ "     ")
           (princ (incf x))
           (princ ". ")
           (if (monster-dead m)
             (princ "**dead**")
             (progn (princ "(Health=")
                    (princ (monster-health m))
                    (princ ") ")
                    (monster-show m))));怪物描述
                  *monsters*)))
;;定义monster的structure
(defstruct monster (health (randval 10)))
;;monster被攻击
(defmethod monster-hit (m x)
  (decf (monster-health m) x)
  (if (monster-dead m)
    (progn (princ "You killed the ")
           (princ (type-of m))
           (princ "! "))
    (progn (princ "You hit the ")
           (princ (type-of m))
           (princ ", knocking off ")
           (princ x)
           (princ " health points! "))))
;;(type-of (make-monster))
;;;;MONSTER
;;;总体定义下
(defmethod monster-show (m)
  (princ "A fierce ")
  (princ (type-of m)))
;;占位
(defmethod monster-attack (m))
;;;orc
;;;defstruct还可以这样定义
(defstruct (orc (:include monster)) (club-level (randval 8)))
(push #'make-orc *monster-builders*)
(defmethod monster-show ((m orc));something like "defmethod function ((a number) (b string))"
  (princ "A wicked orc with a level ")
  (princ (orc-club-level m))
  (princ " club"))
(defmethod monster-attack ((m orc))
  (let ((x (randval (orc-club-level m))))
    (princ "An orc swings his club at you and knocks off ")
    (princ x)
    (princ " of your health points. ")
    (decf *player-health* x)))
;;;hydra,多头鸟
(defstruct (hydra (:include monster)))
(push #'make-hydra *monster-builders*)
(defmethod monster-show ((m hydra))
  (princ "A malicious hydra with ")
  (princ (monster-health m))
  (princ " heads."))
(defmethod monster-hit ((m hydra) x);x代表头数
  (decf (monster-health m) x)
  (if (monster-dead m)
    (princ "The corpse of the fully decapitated and decapacitated hydra
           falls to the floor!")
    (progn (princ "You lop off ")
           (princ x)
           (princ " of the hydra's heads! "))))
(defmethod monster-attack ((m hydra))
  (let ((x (randval (ash (monster-health m) -1))))
    (princ "A hydra attacks you with ")
    (princ x)
    (princ " of its heads! It also grows back one more head! ")
    (incf (monster-health m))
    (decf *player-health* x)))
;;;slime
(defstruct (slime-mold (:include monster)) (sliminess (randval 5)))
(push #'make-slime-mold *monster-builders*)
(defmethod monster-show ((m slime-mold))
  (princ "A slime mold with a sliminess of ")
  (princ (slime-mold-sliminess m)))
(defmethod monster-attack ((m slime-mold))
  (let ((x (randval (slime-mold-sliminess m))))
    (princ "A slime mold wraps around your legs and decreases your agility
           by ")
    (princ x)
    (princ "! ")
    (decf *player-agility* x)
    ;;为了防止进入永无止境的僵持,使slime有几率攻击
    (when (zerop (random 2))
      (princ "It also squirts in your face, taking away a health point! ")
      (decf *player-health*))))
;The Cunning Brigand
(defstruct (brigand (:include monster)))
(push #'make-brigand *monster-builders*)
(defmethod monster-attack ((m brigand))
  (let ((x (max *player-health* *player-agility* *player-strength*)))
    (cond ((= x *player-health*)
           (princ "A brigand hits you with his slingshot, taking off 2 health
                  points! ")
                  (decf *player-health* 2))
          ((= x *player-agility*)
           (princ "A brigand catches your leg with his whip, taking off 2
                  agility points! ")
           (decf *player-agility* 2))
          ((= x *player-strength*)
           (princ "A brigand cuts your arm with his whip, taking off 2
                  strength points! ")
           (decf *player-strength* 2)))))

然后这样开始游戏

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(orc-battle)

不过游戏参数貌似设置的不太好，我基本是出来被秒的！！