closes #16

Author: bckohan

doc/requirements.txt

@@ -6,4 +6,4 @@ sphinxcontrib-htmlhelp==2.0.0; python_version >= "3.5"
 sphinxcontrib-jsmath==1.0.1; python_version >= "3.5"
 sphinxcontrib-qthelp==1.0.3; python_version >= "3.5"
 sphinxcontrib-serializinghtml==1.1.5; python_version >= "3.5"
-enum-properties==1.2.1
+enum-properties==1.2.2

doc/source/changelog.rst

@@ -2,6 +2,11 @@
 Change Log
 ==========
 
+v1.2.2
+======
+
+* Implemented `Add convenience property to decompose Flag enumeration values <https://github.com/bckohan/enum-properties/issues/16>`_
+
 v1.2.1
 ======
 

doc/source/usage.rst

@@ -211,6 +211,9 @@ IntFlag_ and Flag_ types that support properties are also provided by the
         # properties for combined flags, that are not listed will be None
         assert (Perm.R | Perm.W).label is None
 
+        # list the active flags:
+        assert (Perm.R | Perm.W | Perm.X).flagged == [Perm.R, Perm.W, Perm.X]
+
 Flag enumerations can also be created from iterables and generators containing
 values or symmetric values.
 

enum_properties/__init__.py

@@ -20,7 +20,7 @@
 import unicodedata
 from collections.abc import Generator, Hashable, Iterable
 
-VERSION = (1, 2, 1)
+VERSION = (1, 2, 2)
 
 __title__ = 'Enum Properties'
 __version__ = '.'.join(str(i) for i in VERSION)
@@ -36,6 +36,7 @@
     'IntFlagProperties',
     'EnumPropertiesMeta',
     'SymmetricMixin',
+    'DecomposeMixin',
     'p',
     's'
 ]
@@ -492,13 +493,36 @@ class IntEnumProperties(
     """
 
 
-class FlagProperties(SymmetricMixin, enum.Flag, metaclass=EnumPropertiesMeta):
+class DecomposeMixin:  # pylint: disable=R0903
+    """
+    A mixin for Flag enumerations that decomposes composite enumeration values
+    into the constituent activated flags.
+    """
+
+    @property
+    def flagged(self):
+        """
+        Returns the list of flags that are activated.
+        """
+        # do import here to keep lib less brittle b/c this is a private
+        # include and may change, rely on CI to find issues
+        from enum import _decompose  # pylint: disable=C0415
+        return _decompose(self.__class__, self._value_)[0]
+
+
+class FlagProperties(
+    DecomposeMixin,
+    SymmetricMixin,
+    enum.Flag,
+    metaclass=EnumPropertiesMeta
+):
     """
     A Flag that supports properties
     """
 
 
 class IntFlagProperties(
+    DecomposeMixin,
     SymmetricMixin,
     enum.IntFlag,
     metaclass=EnumPropertiesMeta

enum_properties/tests/tests.py

@@ -961,6 +961,10 @@ class Perm(
         self.assertFalse(bool(Perm.R & Perm.X))
         self.assertIsNone((Perm.R & Perm.X).label)
 
+        self.assertCountEqual((Perm.R | Perm.W).flagged, [Perm.R, Perm.W])
+        self.assertCountEqual(Perm.RWX.flagged, [Perm.R, Perm.W, Perm.X])
+        self.assertEqual(Perm.R.flagged, [Perm.R])
+
     def test_flag(self):
 
         class Perm(
@@ -1002,3 +1006,8 @@ class Perm(
 
         self.assertFalse(bool(Perm.R & Perm.X))
         self.assertIsNone((Perm.R & Perm.X).label)
+
+        self.assertCountEqual((Perm.R | Perm.W).flagged, [Perm.R, Perm.W])
+        self.assertCountEqual(Perm.RWX.flagged, [Perm.R, Perm.W, Perm.X])
+        self.assertEqual(Perm.R.flagged, [Perm.R])
+        self.assertEqual((Perm.R & Perm.X).flagged, [Perm(0)])

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "enum-properties"
-version = "1.2.1"
+version = "1.2.2"
 description = "Add properties to Python enumeration values with a simple declarative syntax."
 authors = ["Brian Kohan <bckohan@gmail.com>"]
 license = "MIT"