Add a "CharacterFilter" class

[wsowens]

Right now, the Exit class has a lot of specialized code to deal with allowing certain CharacterClasses in, and keeping certain CharacterClasses out.

In the interest of abstraction, we should abstract this code out into a new class, CharacterFilter. We could then painlessly reuse this functionality for items and entities later. This would solve Issue #27 as well.

[wsowens]

I've implemented this feature on the branch class-filter.
Here's a test:

from character import *

class Magical(Character):
    pass

class Brute(Character):
    pass

class Wizard(Magical):
    pass

class Witch(Magical):
    pass

steve = Character()
steve.set_name("steve")
gandalf = Wizard()
gandalf.set_name("gandalf")
bill = Wizard()
bill.set_name("bill")
sabrina = Witch()
sabrina.set_name("sabrina")
rich_piana = Brute()
rich_piana.set_name("rich piana")

filters = {
    "salty_spitoon" : CharFilter(True, [Brute]),
    "no_brutes_allowed" : CharFilter(False, [Brute]),
    "magic_users_club" : CharFilter(True, [Magical]),
    "we're fine with wizards, we just hate bill" : CharFilter(False, [bill])
}

for name, filter in filters.items():
    print("Testing: %s" % name)
    for thing in [steve, gandalf, bill, sabrina, rich_piana, Character, Magical, Wizard, Witch, Brute]:
        print(str(thing).strip(), filter.allows(thing), sep="\t")

Results:

Testing: salty_spitoon
steve	False
gandalf	False
bill	False
sabrina	False
rich piana	True
Default Character	False
Magical	False
Wizard	False
Witch	False
Brute	True
Testing: no_brutes_allowed
steve	True
gandalf	True
bill	True
sabrina	True
rich piana	False
Default Character	True
Magical	True
Wizard	True
Witch	True
Brute	False
Testing: magic_users_club
steve	False
gandalf	True
bill	True
sabrina	True
rich piana	False
Default Character	False
Magical	True
Wizard	True
Witch	True
Brute	False
Testing: we're fine with wizards, we just hate bill
steve	True
gandalf	True
bill	False
sabrina	True
rich piana	True
Default Character	True
Magical	True
Wizard	True
Witch	True
Brute	True

[wsowens]

Now we must rewrite this part of the Exit class, and add this to the item class. After with do the latter, #27 will be effectively solved.

[wsowens]

The location.Exit class now supports the CharFilter, I'm considering this issue closed.