python - Passing class names to dictionary (and parsing order) -

i have code looks following:

class action(object):     ...  class specificaction1(action):     ...  class specificaction2(action):     ... 

they specified in same file. before specification want put dictionary looks this:

actions = {     "specificaction1": specificaction1,     "specificaction2": specificaction2 } 

the idea can import actions dictionary other modules , have 1 dictionary 1 canonical string representation of actions (they sent on network , other places need identifier).

is possible "class pointers" in same way function pointers? , editor complains names undefined before dictionary declared before class definitions - true?

also, if above possible can instantiate class: actions['specificaction2']()?

classes first-class citizens in python, i.e. can treat them other object. point of view construction fine, except have define actions dictionary @ end of file (because unlike other languages order important in python: throw referenceerror otherwise).

there's more. use metaprogramming simplify this. consider (python2.x, syntax bit different in 3.x):

actions = {}  class mymeta(type):     def __init__(cls, name, bases, nmspc):         super(mymeta, cls).__init__(name, bases, nmspc)         if name != "action": # <--- skip base class             actions[name] = cls  class action(object):     __metaclass__ = mymeta     ...  class specificaction1(action):     ...  class specificaction2(action):     ... 

it automatically populate actions dictionary class inherits action class (because action class has mymeta __metaclass__). read more metaprogramming here:

https://python-3-patterns-idioms-test.readthedocs.org/en/latest/metaprogramming.html

as actions['specificaction2'](): yes, create new instance of class, it's valid code.