Have you figured-out a use for the @enum.member and @enum.nonmember decorators (new in Python 3.11)?
“What’s New” says:
Added the member() and nonmember() decorators, to ensure the decorated object is/is not converted to an enum member.
The PSL docs say:
@enum.member
A decorator for use in enums: its target will become a member.
also:
enum members have names and values (the name of Color.RED is RED, the value of Color.BLUE is 3, etc.)
Noting that the “Utilities and Decorators” section is slightly confusing, because class decorators are mixed with others, so one has to read carefully.
“Curiosity killed the cat” and other cautionary tales/tails…
Have added the following decorated staticmethod to a basic enum. It is indeed recognised as a member of the enum, but its value is the method-object. To gain the value the method-object represents (property-like behavior) one has to call the method/enum-value as a function:-
from enum import Enum, member
class MenuOptions( Enum ):
""" Legal menu-choices. """
N = "NewGame"
L = "LoadGame"
# ...
@member
@staticmethod
def extra_member()->str:
return "QuitGame"
def print_demo( enum_chosen:MenuOptions )->None:
""" Illustrative printing. """
print( "Name:", enum_chosen, enum_chosen.name )
if isinstance( enum_chosen, MenuOptions ):
print( "Value:", enum_chosen.value )
print( MenuOptions.__members__ )
# {'N': <MenuOptions.N: 'NewGame'>, 'L': <MenuOptions.L: 'LoadGame'>, 'extra_member': <MenuOptions.extra_member: <staticmethod(<function MenuOptions.extra_member at 0x7f0802128860>)>>}
print_demo( MenuOptions[ "L" ] )
# Name: MenuOptions.L L
# Value: LoadGame
print_demo( MenuOptions.extra_member )
# Name: MenuOptions.extra_member extra_member
# Value: <staticmethod(<function MenuOptions.extra_member at 0x7f0802128860>)>
print( MenuOptions.extra_member.value() )
# QuitGame
Therefore, like an @property decorator applied to a method in a custom-class, it could be used to evaluate some ‘expensive’ computation only if/when such is needed. Similarly, it could use the other values within the enum in order to present some ‘combination’.
Weirdly (given that enums are considered immutable) I imagine that if the ‘extra_member’ were to call some external function with varying output, the value could be considered mutable when it is eventually called.
Perhaps I have the wrong end of the stick? Other?better ideas…