enum-properties

Enum Properties

Add properties to Python enumeration values with a simple declarative syntax. Enum Properties is a lightweight extension to Python's Enum class. Example:

import typing as t
from enum_properties import EnumProperties
from enum import auto


class Color(EnumProperties):

    rgb: t.Tuple[int, int, int]
    hex: str

    # name   value      rgb       hex
    RED    = auto(), (1, 0, 0), 'ff0000'
    GREEN  = auto(), (0, 1, 0), '00ff00'
    BLUE   = auto(), (0, 0, 1), '0000ff'

# the type hints on the Enum class become properties on
# each value, matching the order in which they are specified


assert Color.RED.rgb   == (1, 0, 0)
assert Color.GREEN.rgb == (0, 1, 0)
assert Color.BLUE.rgb  == (0, 0, 1)

assert Color.RED.hex   == 'ff0000'
assert Color.GREEN.hex == '00ff00'
assert Color.BLUE.hex  == '0000ff'

Properties may also be symmetrically mapped to enumeration values using annotated type hints:

import typing as t
from enum_properties import EnumProperties, Symmetric
from enum import auto


class Color(EnumProperties):

    rgb: t.Annotated[t.Tuple[int, int, int], Symmetric()]
    hex: t.Annotated[str, Symmetric(case_fold=True)]

    RED    = auto(), (1, 0, 0), 'ff0000'
    GREEN  = auto(), (0, 1, 0), '00ff00'
    BLUE   = auto(), (0, 0, 1), '0000ff'

# Enumeration instances may be instantiated from any Symmetric property
# values. Use case_fold for case insensitive matching


assert Color((1, 0, 0)) is Color.RED
assert Color((0, 1, 0)) is Color.GREEN
assert Color((0, 0, 1)) is Color.BLUE

assert Color('ff0000') is Color.RED
assert Color('FF0000') is Color.RED  # case_fold makes mapping case insensitive
assert Color('00ff00') is Color.GREEN
assert Color('00FF00') is Color.GREEN
assert Color('0000ff') is Color.BLUE
assert Color('0000FF') is Color.BLUE

assert Color.RED.hex == 'ff0000'

Member functions may also be specialized to each enumeration value, using the @specialize decorator.

from enum_properties import EnumProperties as Enum, specialize


class SpecializedEnum(Enum):

    ONE   = 1
    TWO   = 2
    THREE = 3

    @specialize(ONE)
    def method(self):
        return 'method_one()'

    @specialize(TWO)
    def method(self):
        return 'method_two()'

    @specialize(THREE)
    def method(self):
        return 'method_three()'

assert SpecializedEnum.ONE.method() == 'method_one()'
assert SpecializedEnum.TWO.method() == 'method_two()'
assert SpecializedEnum.THREE.method() == 'method_three()'

Please report bugs and discuss features on the issues page.

Contributions are encouraged!

Full documentation at read the docs.

Installation

• Clone enum-properties from GitHub or install a release off PyPI:

       pip install enum-properties