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authorGeorg Brandl <georg@python.org>2010-12-30 21:33:07 (GMT)
committerGeorg Brandl <georg@python.org>2010-12-30 21:33:07 (GMT)
commit7fafbc95c0c963438197c9a43fe893c4ea6fe759 (patch)
tree5c9ceda4bdc5260236a230554b9ed56b8c0cdbd3 /Demo/newmetaclasses/Enum.py
parent6f17e2df29a865a29447531e89fb22be710e382d (diff)
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More cleanup: Move some demos into a dedicated Tools/demo dir, move 2to3 demo to Tools, and remove all the other Demo content.
Diffstat (limited to 'Demo/newmetaclasses/Enum.py')
-rw-r--r--Demo/newmetaclasses/Enum.py177
1 files changed, 0 insertions, 177 deletions
diff --git a/Demo/newmetaclasses/Enum.py b/Demo/newmetaclasses/Enum.py
deleted file mode 100644
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--- a/Demo/newmetaclasses/Enum.py
+++ /dev/null
@@ -1,177 +0,0 @@
-"""Enumeration metaclass."""
-
-class EnumMetaclass(type):
- """Metaclass for enumeration.
-
- To define your own enumeration, do something like
-
- class Color(Enum):
- red = 1
- green = 2
- blue = 3
-
- Now, Color.red, Color.green and Color.blue behave totally
- different: they are enumerated values, not integers.
-
- Enumerations cannot be instantiated; however they can be
- subclassed.
- """
-
- def __init__(cls, name, bases, dict):
- super(EnumMetaclass, cls).__init__(name, bases, dict)
- cls._members = []
- for attr in dict.keys():
- if not (attr.startswith('__') and attr.endswith('__')):
- enumval = EnumInstance(name, attr, dict[attr])
- setattr(cls, attr, enumval)
- cls._members.append(attr)
-
- def __getattr__(cls, name):
- if name == "__members__":
- return cls._members
- raise AttributeError(name)
-
- def __repr__(cls):
- s1 = s2 = ""
- enumbases = [base.__name__ for base in cls.__bases__
- if isinstance(base, EnumMetaclass) and not base is Enum]
- if enumbases:
- s1 = "(%s)" % ", ".join(enumbases)
- enumvalues = ["%s: %d" % (val, getattr(cls, val))
- for val in cls._members]
- if enumvalues:
- s2 = ": {%s}" % ", ".join(enumvalues)
- return "%s%s%s" % (cls.__name__, s1, s2)
-
-class FullEnumMetaclass(EnumMetaclass):
- """Metaclass for full enumerations.
-
- A full enumeration displays all the values defined in base classes.
- """
-
- def __init__(cls, name, bases, dict):
- super(FullEnumMetaclass, cls).__init__(name, bases, dict)
- for obj in cls.__mro__:
- if isinstance(obj, EnumMetaclass):
- for attr in obj._members:
- # XXX inefficient
- if not attr in cls._members:
- cls._members.append(attr)
-
-class EnumInstance(int):
- """Class to represent an enumeration value.
-
- EnumInstance('Color', 'red', 12) prints as 'Color.red' and behaves
- like the integer 12 when compared, but doesn't support arithmetic.
-
- XXX Should it record the actual enumeration rather than just its
- name?
- """
-
- def __new__(cls, classname, enumname, value):
- return int.__new__(cls, value)
-
- def __init__(self, classname, enumname, value):
- self.__classname = classname
- self.__enumname = enumname
-
- def __repr__(self):
- return "EnumInstance(%s, %s, %d)" % (self.__classname, self.__enumname,
- self)
-
- def __str__(self):
- return "%s.%s" % (self.__classname, self.__enumname)
-
-class Enum(metaclass=EnumMetaclass):
- pass
-
-class FullEnum(metaclass=FullEnumMetaclass):
- pass
-
-def _test():
-
- class Color(Enum):
- red = 1
- green = 2
- blue = 3
-
- print(Color.red)
-
- print(repr(Color.red))
- print(Color.red == Color.red)
- print(Color.red == Color.blue)
- print(Color.red == 1)
- print(Color.red == 2)
-
- class ExtendedColor(Color):
- white = 0
- orange = 4
- yellow = 5
- purple = 6
- black = 7
-
- print(ExtendedColor.orange)
- print(ExtendedColor.red)
-
- print(Color.red == ExtendedColor.red)
-
- class OtherColor(Enum):
- white = 4
- blue = 5
-
- class MergedColor(Color, OtherColor):
- pass
-
- print(MergedColor.red)
- print(MergedColor.white)
-
- print(Color)
- print(ExtendedColor)
- print(OtherColor)
- print(MergedColor)
-
-def _test2():
-
- class Color(FullEnum):
- red = 1
- green = 2
- blue = 3
-
- print(Color.red)
-
- print(repr(Color.red))
- print(Color.red == Color.red)
- print(Color.red == Color.blue)
- print(Color.red == 1)
- print(Color.red == 2)
-
- class ExtendedColor(Color):
- white = 0
- orange = 4
- yellow = 5
- purple = 6
- black = 7
-
- print(ExtendedColor.orange)
- print(ExtendedColor.red)
-
- print(Color.red == ExtendedColor.red)
-
- class OtherColor(FullEnum):
- white = 4
- blue = 5
-
- class MergedColor(Color, OtherColor):
- pass
-
- print(MergedColor.red)
- print(MergedColor.white)
-
- print(Color)
- print(ExtendedColor)
- print(OtherColor)
- print(MergedColor)
-
-if __name__ == '__main__':
- _test()
- _test2()