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author | Georg Brandl <georg@python.org> | 2010-12-30 21:33:07 (GMT) |
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committer | Georg Brandl <georg@python.org> | 2010-12-30 21:33:07 (GMT) |
commit | 7fafbc95c0c963438197c9a43fe893c4ea6fe759 (patch) | |
tree | 5c9ceda4bdc5260236a230554b9ed56b8c0cdbd3 /Demo/newmetaclasses/Enum.py | |
parent | 6f17e2df29a865a29447531e89fb22be710e382d (diff) | |
download | cpython-7fafbc95c0c963438197c9a43fe893c4ea6fe759.zip cpython-7fafbc95c0c963438197c9a43fe893c4ea6fe759.tar.gz cpython-7fafbc95c0c963438197c9a43fe893c4ea6fe759.tar.bz2 |
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.py | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/Demo/newmetaclasses/Enum.py b/Demo/newmetaclasses/Enum.py deleted file mode 100644 index 3ff8ddd..0000000 --- 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() |