various issues with enum.{IntEnum,Flag,IntFlag}

[anntzer]

• PrettyPrinter version: 0.18.0
• Python version: 3.0
• Operating System: linux

Description

The prettyrepr of {IntEnum,Flag,IntFlag} instances is less than optimal.

What I Did

from enum import Enum, IntEnum, Flag, IntFlag
from prettyprinter import cpprint

for base in [Enum, IntEnum, Flag, IntFlag]:
    class A(base):
        a = 1; b = 2
    print(base)
    cpprint(A.a)
    print(A.a)
    if issubclass(base, Flag):
        cpprint(A.a | A.b)
        print(A.a | A.b)
    print()

yields

<enum 'Enum'>
A.a  # ok
A.a  # (reference)

<enum 'IntEnum'>
A(<A.a: 1>)  # non eval'able; should either be "A.a" (better) or "1" (worse)
A.a  # (reference)

<enum 'Flag'>
A.a  # ok
A.a  # (reference)
A.None  # wrong
A.b|a  # (reference)

<enum 'IntFlag'>
A(<A.a: 1>)  # same issue as with IntEnum
A.a  # (reference)
A(<A.b|a: 3>)  # non eval'able, but I think the non-evalable form "A.b|a" is clearly best
A.b|a  # (reference)

[asford]

Also breaks common class StringEnum(str, Enum) style declarations... 😠

@register_pretty('enum.Enum')
@register_pretty('enum.IntEnum')
@register_pretty('enum.Flag')
@register_pretty('enum.IntFlag')
@register_pretty('enum.StrEnum')
def pretty_enum_custom(value, ctx):
    cls = type(value)
    if value.name is not None:
        return classattr(cls, value.name)
    else:  # Combined flags.
        s = str(value)
        prefix = cls.__name__ + "."
        assert s.startswith(prefix)
        return classattr(cls, s[len(prefix):])

@prettyprinter.register_pretty(str)
def pretty_str_custom(v, ctx, *args, **kwargs):
    if isinstance(v, enum.Enum):
        return prettyprinter.pretty_stdlib.pretty_enum(v, ctx)
    else:
        return prettyprinter.pretty_stdlib.pretty_str(v, ctx)

Much better! 🌴 😌