[Tutor] python game error

[Peter Otten]

bob gailer wrote:


> ------------ Python coding "trick"1  ------------
> when I build a map I omit the () after the class e.g. 'death' = Death, 
> ... and apply them to the item retrieved from the map.
> 
> use a decorator to build the map dictionary:
> 
> # the decorator function:
> def add_to_map(cls, map={}): # map is initialized to a {} when function 
> is "compiled"
>      if cls:
>          map[cls.__name__] = cls # add entry to dictionary
>          return cls
>      else: return map
> 
> # apply decorator to class definitions
> # this will add 'Death': <class '__main__.Death'>
> @add_to_map
> class Death(Scene):
>      class_definition
> 
>   # ditto for all other classes based on Scene - then
> 
> class Map:
>      scenes  = add_to_map() # note when map is called with no arguments 
> it returns the dictionary

Hm, you have now replaced the dead simple

> class Map(object):
>     scenes = {
>     'central_corridor': CentralCorridor(),
>     'laser_weapon_armory': LaserWeaponArmory(),
>     'the_bridge': TheBridge(),
>     'escape_pod': EscapePod(),
>     'death': Death()
>     }

with a class decorator, a dunder name, a mutable default argument -- lots of 
clever Python specific stuff that I wouldn't put on a beginner's list of top 
priorities.

Don't use unless you spotted at least one bug in the code sample at first 
glance :)

By the way, you do not need a map (dict) at all to implement a game like 
this, you may return the next scene directly. A sketch:

class Bridge:
    def enter(self):
        ...
        action = ...
        if action == "jump off the bridge":
            return Death("You are eaten by the piranhas")
        else:
            ...