艰难学Python第41课额外学分

Question

我正在学习《Learn Python the Hard Way》，现在在第41个练习的额外任务上遇到了困难：

额外任务：

1. 给游戏添加作弊码，这样你就可以轻松通过更难的房间。
2. 不要让每个函数自己打印内容，了解一下“文档字符串”的注释风格。把房间描述写成文档注释，然后修改运行程序来打印这些描述。
3. 一旦你把房间描述写成文档注释，真的还需要函数提示吗？让运行程序提示用户，然后把这个输入传递给每个函数。你的函数应该只是一些条件判断，打印结果并返回下一个房间。

根据我目前的理解，使用文档字符串的做法似乎不太被推荐，但这是我想到的：

from sys import exit
from random import randint

globvar = ''

def death():
    quips = ["You died.  You kinda suck at this.",
             "Nice job, you died ...jackass.",
             "Such a loser.",
             "I have a small puppy that's better at this."]

    print quips[randint(0, len(quips)-1)]
    exit(1)


def central_corridor():
    """The Gothons of Planet Percal #25 have invaded your ship and destroyed
    your entire crew.  You are the last surviving member and your last
    mission is to get the neutron destruct bomb from the Weapons Armory,
    put it in the bridge, and blow the ship up after getting into an 
    escape pod.

    You're running down the central corridor to the Weapons Armory when
    a Gothon jumps out, red scaly skin, dark grimy teeth, and evil clown costume
    flowing around his hate filled body.  He's blocking the door to the
    Armory and about to pull a weapon to blast you.
    """

    action = globvar

    if action == "shoot!":
        print "Quick on the draw you yank out your blaster and fire it at the Gothon."
        print "His clown costume is flowing and moving around his body, which throws"
        print "off your aim.  Your laser hits his costume but misses him entirely.  This"
        print "completely ruins his brand new costume his mother bought him, which"
        print "makes him fly into an insane rage and blast you repeatedly in the face until"
        print "you are dead.  Then he eats you."
        return 'death'

    elif action == "dodge!":
        print "Like a world class boxer you dodge, weave, slip and slide right"
        print "as the Gothon's blaster cranks a laser past your head."
        print "In the middle of your artful dodge your foot slips and you"
        print "bang your head on the metal wall and pass out."
        print "You wake up shortly after only to die as the Gothon stomps on"
        print "your head and eats you."
        return 'death'

    elif action == "tell a joke":
        print "Lucky for you they made you learn Gothon insults in the academy."
        print "You tell the one Gothon joke you know:"
        print "Lbhe zbgure vf fb sng, jura fur fvgf nebhaq gur ubhfr, fur fvgf nebhaq gur ubhfr."
        print "The Gothon stops, tries not to laugh, then busts out laughing and can't move."
        print "While he's laughing you run up and shoot him square in the head"
        print "putting him down, then jump through the Weapon Armory door."
        return 'laser_weapon_armory'

    else:
        print "DOES NOT COMPUTE!"
        return 'central_corridor'

def laser_weapon_armory():
    """You do a dive roll into the Weapon Armory, crouch and scan the room
    for more Gothons that might be hiding.  It's dead quiet, too quiet.
    You stand up and run to the far side of the room and find the
    neutron bomb in its container.  There's a keypad lock on the box
    and you need the code to get the bomb out.  If you get the code
    wrong 10 times then the lock closes forever and you can't
    get the bomb.  The code is 3 digits.
    """
    code = "%d%d%d" % (randint(1,9), randint(1,9), randint(1,9))
    guess = globvar
    guesses = 0
    cheat = '007'

    while guess != code and guess != cheat and guesses < 10:
        print "BZZZZEDDD!"
        guesses += 1
        guess = raw_input("[keypad]> ")

    if guess == code:
        print "The container clicks open and the seal breaks, letting gas out."
        print "You grab the neutron bomb and run as fast as you can to the"
        print "bridge where you must place it in the right spot."
        return 'the_bridge'
    elif guess == cheat:
        print "The container clicks open and the seal breaks, letting gas out."
        print "You grab the neutron bomb and run as fast as you can to the"
        print "bridge where you must place it in the right spot."
        return 'the_bridge'
    else:
        print "The lock buzzes one last time and then you hear a sickening"
        print "melting sound as the mechanism is fused together."
        print "You decide to sit there, and finally the Gothons blow up the"
        print "ship from their ship and you die."
        return 'death'


def the_bridge():
    """You burst onto the Bridge with the netron destruct bomb
    under your arm and surprise 5 Gothons who are trying to
    take control of the ship.  Each of them has an even uglier
    clown costume than the last.  They haven't pulled their
    weapons out yet, as they see the active bomb under your
    arm and don't want to set it off.
    """

    action = globvar

    if action == "throw the bomb":
        print "In a panic you throw the bomb at the group of Gothons"
        print "and make a leap for the door.  Right as you drop it a"
        print "Gothon shoots you right in the back killing you."
        print "As you die you see another Gothon frantically try to disarm"
        print "the bomb. You die knowing they will probably blow up when"
        print "it goes off."
        return 'death'

    elif action == "slowly place the bomb":
        print "You point your blaster at the bomb under your arm"
        print "and the Gothons put their hands up and start to sweat."
        print "You inch backward to the door, open it, and then carefully"
        print "place the bomb on the floor, pointing your blaster at it."
        print "You then jump back through the door, punch the close button"
        print "and blast the lock so the Gothons can't get out."
        print "Now that the bomb is placed you run to the escape pod to"
        print "get off this tin can."
        return 'escape_pod'
    else:
        print "DOES NOT COMPUTE!"
        return "the_bridge"

def escape_pod():
    """You rush through the ship desperately trying to make it to
    the escape pod before the whole ship explodes.  It seems like
    hardly any Gothons are on the ship, so your run is clear of
    interference.  You get to the chamber with the escape pods, and
    now need to pick one to take.  Some of them could be damaged
    but you don't have time to look.  There's 5 pods, which one
    do you take?
    """

    good_pod = randint(1,5)
    guess = globvar
    great_pod = 1

    if int(guess) == good_pod:
        print "You jump into pod %s and hit the eject button." % guess
        print "The pod easily slides out into space heading to"
        print "the planet below.  As it flies to the planet, you look"
        print "back and see your ship implode then explode like a"
        print "bright star, taking out the Gothon ship at the same"
        print "time.  You won!"
        exit(0)
    elif int(guess) == great_pod:
        print "You jump into pod %s and hit the eject button." % guess
        print "The pod easily slides out into space heading to"
        print "the planet below.  As it flies to the planet, you look"
        print "back and see your ship implode then explode like a"
        print "bright star, taking out the Gothon ship at the same"
        print "time.  You won!"
        exit(0)
    else:
        print "You jump into pod %s and hit the eject button." % guess
        print "The pod escapes out into the void of space, then"
        print "implodes as the hull ruptures, crushing your body"
        print "into jam jelly."
        return 'death'


ROOMS = {
    'death': death,
    'central_corridor': central_corridor,
    'laser_weapon_armory': laser_weapon_armory,
    'the_bridge': the_bridge,
    'escape_pod': escape_pod
}


def runner(themap, start):
    next = start

    while True:
        ## Global variable in order to pass prompt value to rooms        
        global globvar

        room = themap[next]

        print "\n--------"
        print room.__doc__

        ## Room dependent prompts

        if room == laser_weapon_armory:
            prompt = raw_input("[keypad]> ")
        elif room == escape_pod:
            prompt = raw_input("[pod #]> ")
        elif room == death:
            return 'death'
        else:
            prompt = raw_input("> ")

        ## Set raw_input from prompt to Global variable (globvar)
        globvar = prompt

        next = room()

runner(ROOMS, 'central_corridor')

除了“return 'death'”之外，其他部分运行得很好。它在打印以下内容后就直接退出了：

--------
None

在底部的运行函数中，我以为加上'elif room == death:'这一部分会有效，因为如果没有它，程序就会卡住，等待输入，然后在我按下ENTER后打印一个随机的“俏皮话”。有人能帮我理解我缺少了什么吗？任何帮助都很感激！

编辑 感谢一些快速的反馈，这是我目前的结果，虽然rocksportrocker的解决方案更简单：

def runner(themap, start):
    next = start

    while True:
        ## Global variable in order to pass prompt value to rooms        
        global globvar

        room = themap[next]

        ## Room dependent prompts

        if room == laser_weapon_armory:
            print "\n--------"
            print room.__doc__
            prompt = raw_input("[keypad]> ")
        elif room == escape_pod:
            print "\n--------"
            print room.__doc__
            prompt = raw_input("[pod #]> ")
        elif room == the_bridge:
            print "\n--------"
            print room.__doc__
            prompt = raw_input("> ")
        elif room == central_corridor:
            print "\n--------"
            print room.__doc__
            prompt = raw_input("> ")
        else:
            pass

        ## Set raw_input from prompt to Global variable (globvar)
        globvar = prompt

        next = room()

Answer 1

death这个东西没有文档说明。如果你写了条件 room==death，那么执行 print room.__doc__ 会显示 None，也就是说没有任何说明。在接下来的条件判断中，如果你从函数 runner 返回了某个值，就会导致程序结束。

如果你想让程序正常运行，可以给 death 添加一个文档说明，并且把 runner() 中的 return "death" 改成简单的 pass，或者直接去掉对应的 elif 条件。