2000-02-04 11:39:30 -04:00
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"""Generic (shallow and deep) copying operations.
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1995-01-09 20:34:21 -04:00
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1995-02-09 13:18:10 -04:00
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Interface summary:
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2001-01-14 19:36:06 -04:00
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import copy
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1995-02-09 13:18:10 -04:00
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2001-01-14 19:36:06 -04:00
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x = copy.copy(y) # make a shallow copy of y
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x = copy.deepcopy(y) # make a deep copy of y
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1995-02-09 13:18:10 -04:00
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2003-02-06 15:53:22 -04:00
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For module specific errors, copy.Error is raised.
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1995-02-09 13:18:10 -04:00
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The difference between shallow and deep copying is only relevant for
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compound objects (objects that contain other objects, like lists or
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class instances).
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- A shallow copy constructs a new compound object and then (to the
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2005-06-12 22:10:15 -03:00
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extent possible) inserts *the same objects* into it that the
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1995-02-09 13:18:10 -04:00
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original contains.
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- A deep copy constructs a new compound object and then, recursively,
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inserts *copies* into it of the objects found in the original.
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Two problems often exist with deep copy operations that don't exist
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with shallow copy operations:
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1997-05-28 16:31:14 -03:00
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a) recursive objects (compound objects that, directly or indirectly,
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1995-02-09 13:18:10 -04:00
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contain a reference to themselves) may cause a recursive loop
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1997-05-28 16:31:14 -03:00
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b) because deep copy copies *everything* it may copy too much, e.g.
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1995-02-09 13:18:10 -04:00
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administrative data structures that should be shared even between
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copies
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Python's deep copy operation avoids these problems by:
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1997-05-28 16:31:14 -03:00
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a) keeping a table of objects already copied during the current
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copying pass
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1995-02-09 13:18:10 -04:00
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1997-05-28 16:31:14 -03:00
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b) letting user-defined classes override the copying operation or the
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1995-02-09 13:18:10 -04:00
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set of components copied
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This version does not copy types like module, class, function, method,
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nor stack trace, stack frame, nor file, socket, window, nor array, nor
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any similar types.
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Classes can use the same interfaces to control copying that they use
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to control pickling: they can define methods called __getinitargs__(),
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1997-12-07 12:18:22 -04:00
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__getstate__() and __setstate__(). See the documentation for module
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1995-02-09 13:18:10 -04:00
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"pickle" for information on these methods.
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"""
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1995-01-09 20:34:21 -04:00
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import types
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2009-05-15 13:54:52 -03:00
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import weakref
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2008-05-20 04:49:57 -03:00
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from copy_reg import dispatch_table
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1995-01-09 20:34:21 -04:00
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2000-08-17 02:06:49 -03:00
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class Error(Exception):
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2001-01-14 19:36:06 -04:00
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pass
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error = Error # backward compatibility
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1995-01-09 20:34:21 -04:00
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2000-11-27 17:53:14 -04:00
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try:
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from org.python.core import PyStringMap
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except ImportError:
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PyStringMap = None
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2003-02-06 15:53:22 -04:00
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__all__ = ["Error", "copy", "deepcopy"]
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2001-01-20 15:54:20 -04:00
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1995-01-09 20:34:21 -04:00
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def copy(x):
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2001-01-14 19:36:06 -04:00
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"""Shallow copy operation on arbitrary Python objects.
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See the module's __doc__ string for more info.
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"""
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2003-02-07 13:30:18 -04:00
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cls = type(x)
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copier = _copy_dispatch.get(cls)
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if copier:
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return copier(x)
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copier = getattr(cls, "__copy__", None)
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if copier:
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return copier(x)
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reductor = dispatch_table.get(cls)
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2003-02-18 21:19:28 -04:00
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if reductor:
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rv = reductor(x)
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else:
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reductor = getattr(x, "__reduce_ex__", None)
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if reductor:
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rv = reductor(2)
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else:
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reductor = getattr(x, "__reduce__", None)
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if reductor:
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rv = reductor()
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else:
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raise Error("un(shallow)copyable object of type %s" % cls)
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return _reconstruct(x, rv, 0)
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2003-02-18 22:35:07 -04:00
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2003-02-06 15:53:22 -04:00
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1995-01-09 20:34:21 -04:00
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_copy_dispatch = d = {}
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2004-03-08 01:59:33 -04:00
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def _copy_immutable(x):
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2001-01-14 19:36:06 -04:00
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return x
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2005-02-07 10:16:21 -04:00
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for t in (type(None), int, long, float, bool, str, tuple,
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2004-03-08 01:59:33 -04:00
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frozenset, type, xrange, types.ClassType,
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2008-03-24 05:17:39 -03:00
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types.BuiltinFunctionType, type(Ellipsis),
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2009-05-15 13:54:52 -03:00
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types.FunctionType, weakref.ref):
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2004-03-08 01:59:33 -04:00
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d[t] = _copy_immutable
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for name in ("ComplexType", "UnicodeType", "CodeType"):
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t = getattr(types, name, None)
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if t is not None:
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d[t] = _copy_immutable
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def _copy_with_constructor(x):
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return type(x)(x)
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for t in (list, dict, set):
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d[t] = _copy_with_constructor
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def _copy_with_copy_method(x):
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2001-01-14 19:36:06 -04:00
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return x.copy()
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2000-11-27 17:53:14 -04:00
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if PyStringMap is not None:
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2004-03-08 01:59:33 -04:00
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d[PyStringMap] = _copy_with_copy_method
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1995-01-09 20:34:21 -04:00
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def _copy_inst(x):
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2001-01-14 19:36:06 -04:00
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if hasattr(x, '__copy__'):
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return x.__copy__()
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if hasattr(x, '__getinitargs__'):
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args = x.__getinitargs__()
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2003-02-27 16:14:51 -04:00
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y = x.__class__(*args)
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2001-01-14 19:36:06 -04:00
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else:
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y = _EmptyClass()
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y.__class__ = x.__class__
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if hasattr(x, '__getstate__'):
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state = x.__getstate__()
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else:
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state = x.__dict__
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if hasattr(y, '__setstate__'):
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y.__setstate__(state)
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else:
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y.__dict__.update(state)
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return y
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1995-01-09 20:34:21 -04:00
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d[types.InstanceType] = _copy_inst
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del d
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2003-02-07 13:30:18 -04:00
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def deepcopy(x, memo=None, _nil=[]):
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2001-01-14 19:36:06 -04:00
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"""Deep copy operation on arbitrary Python objects.
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See the module's __doc__ string for more info.
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"""
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if memo is None:
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memo = {}
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2003-02-07 13:30:18 -04:00
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2001-01-14 19:36:06 -04:00
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d = id(x)
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2003-02-07 13:30:18 -04:00
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y = memo.get(d, _nil)
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if y is not _nil:
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return y
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cls = type(x)
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copier = _deepcopy_dispatch.get(cls)
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if copier:
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y = copier(x, memo)
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else:
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2001-01-14 19:36:06 -04:00
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try:
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2003-02-07 13:30:18 -04:00
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issc = issubclass(cls, type)
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except TypeError: # cls is not a class (old Boost; see SF #502085)
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2002-06-10 18:10:27 -03:00
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issc = 0
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if issc:
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2003-02-18 21:19:28 -04:00
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y = _deepcopy_atomic(x, memo)
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2003-02-07 13:30:18 -04:00
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else:
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2003-02-18 21:19:28 -04:00
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copier = getattr(x, "__deepcopy__", None)
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if copier:
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y = copier(memo)
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else:
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reductor = dispatch_table.get(cls)
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if reductor:
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rv = reductor(x)
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else:
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reductor = getattr(x, "__reduce_ex__", None)
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if reductor:
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rv = reductor(2)
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else:
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reductor = getattr(x, "__reduce__", None)
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if reductor:
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rv = reductor()
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else:
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raise Error(
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"un(deep)copyable object of type %s" % cls)
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y = _reconstruct(x, rv, 1, memo)
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2003-02-07 13:30:18 -04:00
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2001-01-14 19:36:06 -04:00
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memo[d] = y
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2002-08-12 17:20:08 -03:00
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_keep_alive(x, memo) # Make sure x lives at least as long as d
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2001-01-14 19:36:06 -04:00
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return y
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1995-01-09 20:34:21 -04:00
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_deepcopy_dispatch = d = {}
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def _deepcopy_atomic(x, memo):
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2001-01-14 19:36:06 -04:00
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return x
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2005-02-07 10:16:21 -04:00
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d[type(None)] = _deepcopy_atomic
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2008-03-24 05:17:39 -03:00
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d[type(Ellipsis)] = _deepcopy_atomic
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2005-02-07 10:16:21 -04:00
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d[int] = _deepcopy_atomic
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d[long] = _deepcopy_atomic
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d[float] = _deepcopy_atomic
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d[bool] = _deepcopy_atomic
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2001-09-28 15:16:13 -03:00
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try:
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2005-02-07 10:16:21 -04:00
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d[complex] = _deepcopy_atomic
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2005-03-08 11:03:08 -04:00
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except NameError:
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2001-09-28 15:16:13 -03:00
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pass
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2005-02-07 10:16:21 -04:00
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d[str] = _deepcopy_atomic
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2001-08-17 15:39:25 -03:00
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try:
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2005-02-07 10:16:21 -04:00
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d[unicode] = _deepcopy_atomic
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2005-03-08 11:03:08 -04:00
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except NameError:
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2001-08-17 15:39:25 -03:00
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pass
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2002-02-28 19:19:52 -04:00
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try:
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d[types.CodeType] = _deepcopy_atomic
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except AttributeError:
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pass
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2005-02-07 10:16:21 -04:00
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d[type] = _deepcopy_atomic
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d[xrange] = _deepcopy_atomic
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2003-02-07 13:53:23 -04:00
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d[types.ClassType] = _deepcopy_atomic
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2003-06-14 04:10:06 -03:00
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d[types.BuiltinFunctionType] = _deepcopy_atomic
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2006-02-25 18:38:04 -04:00
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d[types.FunctionType] = _deepcopy_atomic
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2009-05-15 13:54:52 -03:00
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d[weakref.ref] = _deepcopy_atomic
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1995-01-09 20:34:21 -04:00
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def _deepcopy_list(x, memo):
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2001-01-14 19:36:06 -04:00
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y = []
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memo[id(x)] = y
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for a in x:
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y.append(deepcopy(a, memo))
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return y
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2005-02-07 10:16:21 -04:00
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d[list] = _deepcopy_list
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1995-01-09 20:34:21 -04:00
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def _deepcopy_tuple(x, memo):
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2001-01-14 19:36:06 -04:00
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y = []
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for a in x:
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y.append(deepcopy(a, memo))
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d = id(x)
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try:
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return memo[d]
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except KeyError:
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pass
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for i in range(len(x)):
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if x[i] is not y[i]:
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y = tuple(y)
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break
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else:
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y = x
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memo[d] = y
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return y
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2005-02-07 10:16:21 -04:00
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d[tuple] = _deepcopy_tuple
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1995-01-09 20:34:21 -04:00
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def _deepcopy_dict(x, memo):
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2001-01-14 19:36:06 -04:00
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y = {}
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memo[id(x)] = y
|
2002-06-02 15:55:56 -03:00
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for key, value in x.iteritems():
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y[deepcopy(key, memo)] = deepcopy(value, memo)
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2001-01-14 19:36:06 -04:00
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return y
|
2005-02-07 10:16:21 -04:00
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d[dict] = _deepcopy_dict
|
2000-11-27 17:53:14 -04:00
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if PyStringMap is not None:
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|
d[PyStringMap] = _deepcopy_dict
|
1995-01-09 20:34:21 -04:00
|
|
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|
1997-08-20 19:26:19 -03:00
|
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|
def _keep_alive(x, memo):
|
2001-01-14 19:36:06 -04:00
|
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"""Keeps a reference to the object x in the memo.
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|
Because we remember objects by their id, we have
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to assure that possibly temporary objects are kept
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|
alive by referencing them.
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|
We store a reference at the id of the memo, which should
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|
normally not be used unless someone tries to deepcopy
|
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|
the memo itself...
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|
"""
|
|
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|
try:
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|
memo[id(memo)].append(x)
|
|
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|
except KeyError:
|
|
|
|
# aha, this is the first one :-)
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|
|
|
memo[id(memo)]=[x]
|
1997-08-20 19:26:19 -03:00
|
|
|
|
1995-01-09 20:34:21 -04:00
|
|
|
def _deepcopy_inst(x, memo):
|
2001-01-14 19:36:06 -04:00
|
|
|
if hasattr(x, '__deepcopy__'):
|
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|
return x.__deepcopy__(memo)
|
|
|
|
if hasattr(x, '__getinitargs__'):
|
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|
|
args = x.__getinitargs__()
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|
|
|
args = deepcopy(args, memo)
|
2003-02-27 16:14:51 -04:00
|
|
|
y = x.__class__(*args)
|
2001-01-14 19:36:06 -04:00
|
|
|
else:
|
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|
|
y = _EmptyClass()
|
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|
|
y.__class__ = x.__class__
|
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|
memo[id(x)] = y
|
|
|
|
if hasattr(x, '__getstate__'):
|
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|
|
state = x.__getstate__()
|
|
|
|
else:
|
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|
|
state = x.__dict__
|
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|
|
state = deepcopy(state, memo)
|
|
|
|
if hasattr(y, '__setstate__'):
|
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|
|
y.__setstate__(state)
|
|
|
|
else:
|
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|
|
y.__dict__.update(state)
|
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|
|
return y
|
1995-01-09 20:34:21 -04:00
|
|
|
d[types.InstanceType] = _deepcopy_inst
|
|
|
|
|
2001-12-28 17:33:22 -04:00
|
|
|
def _reconstruct(x, info, deep, memo=None):
|
2001-09-28 15:13:29 -03:00
|
|
|
if isinstance(info, str):
|
|
|
|
return x
|
|
|
|
assert isinstance(info, tuple)
|
2001-12-28 17:33:22 -04:00
|
|
|
if memo is None:
|
|
|
|
memo = {}
|
2001-09-28 15:13:29 -03:00
|
|
|
n = len(info)
|
2003-02-06 14:18:23 -04:00
|
|
|
assert n in (2, 3, 4, 5)
|
2001-09-28 15:13:29 -03:00
|
|
|
callable, args = info[:2]
|
|
|
|
if n > 2:
|
|
|
|
state = info[2]
|
|
|
|
else:
|
|
|
|
state = {}
|
2003-02-06 14:18:23 -04:00
|
|
|
if n > 3:
|
|
|
|
listiter = info[3]
|
|
|
|
else:
|
|
|
|
listiter = None
|
|
|
|
if n > 4:
|
|
|
|
dictiter = info[4]
|
|
|
|
else:
|
|
|
|
dictiter = None
|
2001-09-28 15:13:29 -03:00
|
|
|
if deep:
|
2001-12-28 17:33:22 -04:00
|
|
|
args = deepcopy(args, memo)
|
2001-09-28 15:13:29 -03:00
|
|
|
y = callable(*args)
|
2003-06-13 16:28:47 -03:00
|
|
|
memo[id(x)] = y
|
2003-02-06 14:18:23 -04:00
|
|
|
if listiter is not None:
|
|
|
|
for item in listiter:
|
|
|
|
if deep:
|
|
|
|
item = deepcopy(item, memo)
|
|
|
|
y.append(item)
|
|
|
|
if dictiter is not None:
|
|
|
|
for key, value in dictiter:
|
|
|
|
if deep:
|
|
|
|
key = deepcopy(key, memo)
|
|
|
|
value = deepcopy(value, memo)
|
|
|
|
y[key] = value
|
2001-09-28 15:13:29 -03:00
|
|
|
if state:
|
|
|
|
if deep:
|
2001-12-28 17:33:22 -04:00
|
|
|
state = deepcopy(state, memo)
|
2002-06-06 14:41:20 -03:00
|
|
|
if hasattr(y, '__setstate__'):
|
|
|
|
y.__setstate__(state)
|
|
|
|
else:
|
2003-02-06 15:53:22 -04:00
|
|
|
if isinstance(state, tuple) and len(state) == 2:
|
|
|
|
state, slotstate = state
|
|
|
|
else:
|
|
|
|
slotstate = None
|
|
|
|
if state is not None:
|
|
|
|
y.__dict__.update(state)
|
|
|
|
if slotstate is not None:
|
|
|
|
for key, value in slotstate.iteritems():
|
|
|
|
setattr(y, key, value)
|
2001-09-28 15:13:29 -03:00
|
|
|
return y
|
|
|
|
|
1995-01-09 20:34:21 -04:00
|
|
|
del d
|
|
|
|
|
|
|
|
del types
|
|
|
|
|
1997-12-07 12:18:22 -04:00
|
|
|
# Helper for instance creation without calling __init__
|
|
|
|
class _EmptyClass:
|
|
|
|
pass
|
|
|
|
|
1995-01-09 20:34:21 -04:00
|
|
|
def _test():
|
2001-01-14 19:36:06 -04:00
|
|
|
l = [None, 1, 2L, 3.14, 'xyzzy', (1, 2L), [3.14, 'abc'],
|
|
|
|
{'abc': 'ABC'}, (), [], {}]
|
|
|
|
l1 = copy(l)
|
|
|
|
print l1==l
|
|
|
|
l1 = map(copy, l)
|
|
|
|
print l1==l
|
|
|
|
l1 = deepcopy(l)
|
|
|
|
print l1==l
|
|
|
|
class C:
|
|
|
|
def __init__(self, arg=None):
|
|
|
|
self.a = 1
|
|
|
|
self.arg = arg
|
|
|
|
if __name__ == '__main__':
|
|
|
|
import sys
|
|
|
|
file = sys.argv[0]
|
|
|
|
else:
|
|
|
|
file = __file__
|
|
|
|
self.fp = open(file)
|
|
|
|
self.fp.close()
|
|
|
|
def __getstate__(self):
|
|
|
|
return {'a': self.a, 'arg': self.arg}
|
|
|
|
def __setstate__(self, state):
|
2002-06-02 15:55:56 -03:00
|
|
|
for key, value in state.iteritems():
|
|
|
|
setattr(self, key, value)
|
2003-02-07 13:30:18 -04:00
|
|
|
def __deepcopy__(self, memo=None):
|
2001-01-14 19:36:06 -04:00
|
|
|
new = self.__class__(deepcopy(self.arg, memo))
|
|
|
|
new.a = self.a
|
|
|
|
return new
|
|
|
|
c = C('argument sketch')
|
|
|
|
l.append(c)
|
|
|
|
l2 = copy(l)
|
|
|
|
print l == l2
|
|
|
|
print l
|
|
|
|
print l2
|
|
|
|
l2 = deepcopy(l)
|
|
|
|
print l == l2
|
|
|
|
print l
|
|
|
|
print l2
|
|
|
|
l.append({l[1]: l, 'xyz': l[2]})
|
|
|
|
l3 = copy(l)
|
2008-05-23 02:03:59 -03:00
|
|
|
import repr
|
|
|
|
print map(repr.repr, l)
|
|
|
|
print map(repr.repr, l1)
|
|
|
|
print map(repr.repr, l2)
|
|
|
|
print map(repr.repr, l3)
|
2001-01-14 19:36:06 -04:00
|
|
|
l3 = deepcopy(l)
|
2008-05-23 02:03:59 -03:00
|
|
|
import repr
|
|
|
|
print map(repr.repr, l)
|
|
|
|
print map(repr.repr, l1)
|
|
|
|
print map(repr.repr, l2)
|
|
|
|
print map(repr.repr, l3)
|
1995-01-09 20:34:21 -04:00
|
|
|
|
|
|
|
if __name__ == '__main__':
|
2001-01-14 19:36:06 -04:00
|
|
|
_test()
|