Proposal: Flag-based conditions for logical combinations

[chosak]

Right now it's not easily possible to combine conditions using and/or logic, for example, enabling a flag if A and B but not (C or D). This is possible using custom conditions, but that requires writing custom code.

As a workaround, I wonder if it would work to introduce the concept of flag-based conditions, something like:

@register("flag_enabled", validator=valid_flag_name)
def flag_enabled_condition(flag_name, **kwargs):
    return flag_enabled(flag_name, **kwargs)

@register("flag_disabled", validator=valid_flag_name)
def flag_disabled_condition(flag_name, **kwargs):
    return flag_disabled(flag_name, **kwargs)

(This assumes some definition of valid_flag_name that's a regex of some kind - although in docs and by convention we tend to use SCREAMING_SNAKE_CASE, but technically are there any practical limitations on flag names? So perhaps a validator isn't even needed.)

This would allow you to define some flag FOO as C or D and then some other flag BAR as A and B and (FOO disabled).