- Patch 1433928:
- The copy module now "copies" function objects (as atomic objects).
- dict.__getitem__ now looks for a __missing__ hook before raising
KeyError.
- Added a new type, defaultdict, to the collections module.
This uses the new __missing__ hook behavior added to dict (see above).
diff --git a/Doc/lib/libcollections.tex b/Doc/lib/libcollections.tex
index 51603aa..542ef6b 100644
--- a/Doc/lib/libcollections.tex
+++ b/Doc/lib/libcollections.tex
@@ -8,9 +8,10 @@
\versionadded{2.4}
-This module implements high-performance container datatypes. Currently, the
-only datatype is a deque. Future additions may include B-trees
-and Fibonacci heaps.
+This module implements high-performance container datatypes. Currently,
+there are two datatypes, deque and defaultdict.
+Future additions may include B-trees and Fibonacci heaps.
+\versionchanged[Added defaultdict]{2.5}
\begin{funcdesc}{deque}{\optional{iterable}}
Returns a new deque objected initialized left-to-right (using
@@ -211,3 +212,46 @@
[[[['a', 'b'], ['c', 'd']], [['e', 'f'], ['g', 'h']]]]
\end{verbatim}
+
+
+
+\begin{funcdesc}{defaultdict}{\optional{default_factory\optional{, ...}}}
+ Returns a new dictionary-like object. \class{defaultdict} is a subclass
+ of the builtin \class{dict} class. It overrides one method and adds one
+ writable instance variable. The remaining functionality is the same as
+ for the \class{dict} class and is not documented here.
+
+ The first argument provides the initial value for the
+ \member{default_factory} attribute; it defaults to \code{None}.
+ All remaining arguments are treated the same as if they were
+ passed to the \class{dict} constructor, including keyword arguments.
+
+ \versionadded{2.5}
+\end{funcdesc}
+
+\class{defaultdict} objects support the following method in addition to
+the standard \class{dict} operations:
+
+\begin{methoddesc}{__missing__}{key}
+ If the \member{default_factory} attribute is \code{None}, this raises
+ an \exception{KeyError} exception with the \var{key} as argument.
+
+ If \member{default_factory} is not \code{None}, it is called without
+ arguments to provide a default value for the given \var{key}, this
+ value is inserted in the dictionary for the \var{key}, and returned.
+
+ If calling \member{default_factory} raises an exception this exception
+ is propagated unchanged.
+
+ This method is called by the \method{__getitem__} method of the
+ \class{dict} class when the requested key is not found; whatever it
+ returns or raises is then returned or raised by \method{__getitem__}.
+\end{methoddesc}
+
+\class{defaultdict} objects support the following instance variable:
+
+\begin{datadesc}{default_factory}
+ This attribute is used by the \method{__missing__} method; it is initialized
+ from the first argument to the constructor, if present, or to \code{None},
+ if absent.
+\end{datadesc}
diff --git a/Doc/lib/libcopy.tex b/Doc/lib/libcopy.tex
index d73d6fd..5964187 100644
--- a/Doc/lib/libcopy.tex
+++ b/Doc/lib/libcopy.tex
@@ -67,9 +67,12 @@
\end{itemize}
-This version does not copy types like module, class, function, method,
+This module does not copy types like module, method,
stack trace, stack frame, file, socket, window, array, or any similar
-types.
+types. It does ``copy'' functions and classes (shallow and deeply),
+by returning the original object unchanged; this is compatible with
+the way these are treated by the \module{pickle} module.
+\versionchanged[Added copying functions]{2.5}
Classes can use the same interfaces to control copying that they use
to control pickling. See the description of module
diff --git a/Doc/lib/libstdtypes.tex b/Doc/lib/libstdtypes.tex
index 5df39db..5d15375 100644
--- a/Doc/lib/libstdtypes.tex
+++ b/Doc/lib/libstdtypes.tex
@@ -1350,7 +1350,7 @@
\begin{tableiii}{c|l|c}{code}{Operation}{Result}{Notes}
\lineiii{len(\var{a})}{the number of items in \var{a}}{}
- \lineiii{\var{a}[\var{k}]}{the item of \var{a} with key \var{k}}{(1)}
+ \lineiii{\var{a}[\var{k}]}{the item of \var{a} with key \var{k}}{(1), (10)}
\lineiii{\var{a}[\var{k}] = \var{v}}
{set \code{\var{a}[\var{k}]} to \var{v}}
{}
@@ -1454,6 +1454,17 @@
\versionchanged[Allowed the argument to be an iterable of key/value
pairs and allowed keyword arguments]{2.4}
+\item[(10)] If a subclass of dict defines a method \method{__missing__},
+if the key \var{k} is not present, the \var{a}[\var{k}] operation calls
+that method with the key \var{k} as argument. The \var{a}[\var{k}]
+operation then returns or raises whatever is returned or raised by the
+\function{__missing__}(\var{k}) call if the key is not present.
+No other operations or methods invoke \method{__missing__}().
+If \method{__missing__} is not defined, \exception{KeyError} is raised.
+\method{__missing__} must be a method; it cannot be an instance variable.
+For an example, see \module{collections}.\class{defaultdict}.
+\versionadded{2.5}
+
\end{description}
\subsection{File Objects
diff --git a/Lib/UserDict.py b/Lib/UserDict.py
index 7168703..5e97817 100644
--- a/Lib/UserDict.py
+++ b/Lib/UserDict.py
@@ -14,7 +14,12 @@
else:
return cmp(self.data, dict)
def __len__(self): return len(self.data)
- def __getitem__(self, key): return self.data[key]
+ def __getitem__(self, key):
+ if key in self.data:
+ return self.data[key]
+ if hasattr(self.__class__, "__missing__"):
+ return self.__class__.__missing__(self, key)
+ raise KeyError(key)
def __setitem__(self, key, item): self.data[key] = item
def __delitem__(self, key): del self.data[key]
def clear(self): self.data.clear()
diff --git a/Lib/copy.py b/Lib/copy.py
index b3419ca..9e60144 100644
--- a/Lib/copy.py
+++ b/Lib/copy.py
@@ -101,7 +101,8 @@
return x
for t in (type(None), int, long, float, bool, str, tuple,
frozenset, type, xrange, types.ClassType,
- types.BuiltinFunctionType):
+ types.BuiltinFunctionType,
+ types.FunctionType):
d[t] = _copy_immutable
for name in ("ComplexType", "UnicodeType", "CodeType"):
t = getattr(types, name, None)
@@ -217,6 +218,7 @@
d[xrange] = _deepcopy_atomic
d[types.ClassType] = _deepcopy_atomic
d[types.BuiltinFunctionType] = _deepcopy_atomic
+d[types.FunctionType] = _deepcopy_atomic
def _deepcopy_list(x, memo):
y = []
diff --git a/Lib/test/test_copy.py b/Lib/test/test_copy.py
index bd5a3e1..ff4c987 100644
--- a/Lib/test/test_copy.py
+++ b/Lib/test/test_copy.py
@@ -568,6 +568,22 @@
raise ValueError, "ain't got no stickin' state"
self.assertRaises(ValueError, copy.copy, EvilState())
+ def test_copy_function(self):
+ self.assertEqual(copy.copy(global_foo), global_foo)
+ def foo(x, y): return x+y
+ self.assertEqual(copy.copy(foo), foo)
+ bar = lambda: None
+ self.assertEqual(copy.copy(bar), bar)
+
+ def test_deepcopy_function(self):
+ self.assertEqual(copy.deepcopy(global_foo), global_foo)
+ def foo(x, y): return x+y
+ self.assertEqual(copy.deepcopy(foo), foo)
+ bar = lambda: None
+ self.assertEqual(copy.deepcopy(bar), bar)
+
+def global_foo(x, y): return x+y
+
def test_main():
test_support.run_unittest(TestCopy)
diff --git a/Lib/test/test_defaultdict.py b/Lib/test/test_defaultdict.py
new file mode 100644
index 0000000..b5a6628
--- /dev/null
+++ b/Lib/test/test_defaultdict.py
@@ -0,0 +1,135 @@
+"""Unit tests for collections.defaultdict."""
+
+import os
+import copy
+import tempfile
+import unittest
+
+from collections import defaultdict
+
+def foobar():
+ return list
+
+class TestDefaultDict(unittest.TestCase):
+
+ def test_basic(self):
+ d1 = defaultdict()
+ self.assertEqual(d1.default_factory, None)
+ d1.default_factory = list
+ d1[12].append(42)
+ self.assertEqual(d1, {12: [42]})
+ d1[12].append(24)
+ self.assertEqual(d1, {12: [42, 24]})
+ d1[13]
+ d1[14]
+ self.assertEqual(d1, {12: [42, 24], 13: [], 14: []})
+ self.assert_(d1[12] is not d1[13] is not d1[14])
+ d2 = defaultdict(list, foo=1, bar=2)
+ self.assertEqual(d2.default_factory, list)
+ self.assertEqual(d2, {"foo": 1, "bar": 2})
+ self.assertEqual(d2["foo"], 1)
+ self.assertEqual(d2["bar"], 2)
+ self.assertEqual(d2[42], [])
+ self.assert_("foo" in d2)
+ self.assert_("foo" in d2.keys())
+ self.assert_("bar" in d2)
+ self.assert_("bar" in d2.keys())
+ self.assert_(42 in d2)
+ self.assert_(42 in d2.keys())
+ self.assert_(12 not in d2)
+ self.assert_(12 not in d2.keys())
+ d2.default_factory = None
+ self.assertEqual(d2.default_factory, None)
+ try:
+ d2[15]
+ except KeyError, err:
+ self.assertEqual(err.args, (15,))
+ else:
+ self.fail("d2[15] didn't raise KeyError")
+
+ def test_missing(self):
+ d1 = defaultdict()
+ self.assertRaises(KeyError, d1.__missing__, 42)
+ d1.default_factory = list
+ self.assertEqual(d1.__missing__(42), [])
+
+ def test_repr(self):
+ d1 = defaultdict()
+ self.assertEqual(d1.default_factory, None)
+ self.assertEqual(repr(d1), "defaultdict(None, {})")
+ d1[11] = 41
+ self.assertEqual(repr(d1), "defaultdict(None, {11: 41})")
+ d2 = defaultdict(0)
+ self.assertEqual(d2.default_factory, 0)
+ d2[12] = 42
+ self.assertEqual(repr(d2), "defaultdict(0, {12: 42})")
+ def foo(): return 43
+ d3 = defaultdict(foo)
+ self.assert_(d3.default_factory is foo)
+ d3[13]
+ self.assertEqual(repr(d3), "defaultdict(%s, {13: 43})" % repr(foo))
+
+ def test_print(self):
+ d1 = defaultdict()
+ def foo(): return 42
+ d2 = defaultdict(foo, {1: 2})
+ # NOTE: We can't use tempfile.[Named]TemporaryFile since this
+ # code must exercise the tp_print C code, which only gets
+ # invoked for *real* files.
+ tfn = tempfile.mktemp()
+ try:
+ f = open(tfn, "w+")
+ try:
+ print >>f, d1
+ print >>f, d2
+ f.seek(0)
+ self.assertEqual(f.readline(), repr(d1) + "\n")
+ self.assertEqual(f.readline(), repr(d2) + "\n")
+ finally:
+ f.close()
+ finally:
+ os.remove(tfn)
+
+ def test_copy(self):
+ d1 = defaultdict()
+ d2 = d1.copy()
+ self.assertEqual(type(d2), defaultdict)
+ self.assertEqual(d2.default_factory, None)
+ self.assertEqual(d2, {})
+ d1.default_factory = list
+ d3 = d1.copy()
+ self.assertEqual(type(d3), defaultdict)
+ self.assertEqual(d3.default_factory, list)
+ self.assertEqual(d3, {})
+ d1[42]
+ d4 = d1.copy()
+ self.assertEqual(type(d4), defaultdict)
+ self.assertEqual(d4.default_factory, list)
+ self.assertEqual(d4, {42: []})
+ d4[12]
+ self.assertEqual(d4, {42: [], 12: []})
+
+ def test_shallow_copy(self):
+ d1 = defaultdict(foobar, {1: 1})
+ d2 = copy.copy(d1)
+ self.assertEqual(d2.default_factory, foobar)
+ self.assertEqual(d2, d1)
+ d1.default_factory = list
+ d2 = copy.copy(d1)
+ self.assertEqual(d2.default_factory, list)
+ self.assertEqual(d2, d1)
+
+ def test_deep_copy(self):
+ d1 = defaultdict(foobar, {1: [1]})
+ d2 = copy.deepcopy(d1)
+ self.assertEqual(d2.default_factory, foobar)
+ self.assertEqual(d2, d1)
+ self.assert_(d1[1] is not d2[1])
+ d1.default_factory = list
+ d2 = copy.deepcopy(d1)
+ self.assertEqual(d2.default_factory, list)
+ self.assertEqual(d2, d1)
+
+
+if __name__ == "__main__":
+ unittest.main()
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index e13829c..f3f78e7 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -395,6 +395,56 @@
else:
self.fail("< didn't raise Exc")
+ def test_missing(self):
+ # Make sure dict doesn't have a __missing__ method
+ self.assertEqual(hasattr(dict, "__missing__"), False)
+ self.assertEqual(hasattr({}, "__missing__"), False)
+ # Test several cases:
+ # (D) subclass defines __missing__ method returning a value
+ # (E) subclass defines __missing__ method raising RuntimeError
+ # (F) subclass sets __missing__ instance variable (no effect)
+ # (G) subclass doesn't define __missing__ at a all
+ class D(dict):
+ def __missing__(self, key):
+ return 42
+ d = D({1: 2, 3: 4})
+ self.assertEqual(d[1], 2)
+ self.assertEqual(d[3], 4)
+ self.assert_(2 not in d)
+ self.assert_(2 not in d.keys())
+ self.assertEqual(d[2], 42)
+ class E(dict):
+ def __missing__(self, key):
+ raise RuntimeError(key)
+ e = E()
+ try:
+ e[42]
+ except RuntimeError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("e[42] didn't raise RuntimeError")
+ class F(dict):
+ def __init__(self):
+ # An instance variable __missing__ should have no effect
+ self.__missing__ = lambda key: None
+ f = F()
+ try:
+ f[42]
+ except KeyError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("f[42] didn't raise KeyError")
+ class G(dict):
+ pass
+ g = G()
+ try:
+ g[42]
+ except KeyError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("g[42] didn't raise KeyError")
+
+
import mapping_tests
class GeneralMappingTests(mapping_tests.BasicTestMappingProtocol):
diff --git a/Lib/test/test_userdict.py b/Lib/test/test_userdict.py
index 2d5fa03..a4b7de4 100644
--- a/Lib/test/test_userdict.py
+++ b/Lib/test/test_userdict.py
@@ -148,6 +148,55 @@
self.assertEqual(t.popitem(), ("x", 42))
self.assertRaises(KeyError, t.popitem)
+ def test_missing(self):
+ # Make sure UserDict doesn't have a __missing__ method
+ self.assertEqual(hasattr(UserDict, "__missing__"), False)
+ # Test several cases:
+ # (D) subclass defines __missing__ method returning a value
+ # (E) subclass defines __missing__ method raising RuntimeError
+ # (F) subclass sets __missing__ instance variable (no effect)
+ # (G) subclass doesn't define __missing__ at a all
+ class D(UserDict.UserDict):
+ def __missing__(self, key):
+ return 42
+ d = D({1: 2, 3: 4})
+ self.assertEqual(d[1], 2)
+ self.assertEqual(d[3], 4)
+ self.assert_(2 not in d)
+ self.assert_(2 not in d.keys())
+ self.assertEqual(d[2], 42)
+ class E(UserDict.UserDict):
+ def __missing__(self, key):
+ raise RuntimeError(key)
+ e = E()
+ try:
+ e[42]
+ except RuntimeError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("e[42] didn't raise RuntimeError")
+ class F(UserDict.UserDict):
+ def __init__(self):
+ # An instance variable __missing__ should have no effect
+ self.__missing__ = lambda key: None
+ UserDict.UserDict.__init__(self)
+ f = F()
+ try:
+ f[42]
+ except KeyError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("f[42] didn't raise KeyError")
+ class G(UserDict.UserDict):
+ pass
+ g = G()
+ try:
+ g[42]
+ except KeyError, err:
+ self.assertEqual(err.args, (42,))
+ else:
+ self.fail_("g[42] didn't raise KeyError")
+
##########################
# Test Dict Mixin
diff --git a/Misc/NEWS b/Misc/NEWS
index 8429b7b..e5c5e40 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,11 @@
Core and builtins
-----------------
+- Patch 1433928:
+ - The copy module now "copies" function objects (as atomic objects).
+ - dict.__getitem__ now looks for a __missing__ hook before raising
+ KeyError.
+
- Fix the encodings package codec search function to only search
inside its own package. Fixes problem reported in patch #1433198.
@@ -224,6 +229,9 @@
Extension Modules
-----------------
+- Patch 1433928: Added a new type, defaultdict, to the collections module.
+ This uses the new __missing__ hook behavior added to dict (see above).
+
- Bug #854823: socketmodule now builds on Sun platforms even when
INET_ADDRSTRLEN is not defined.
diff --git a/Modules/collectionsmodule.c b/Modules/collectionsmodule.c
index 7368d80..b80ab07 100644
--- a/Modules/collectionsmodule.c
+++ b/Modules/collectionsmodule.c
@@ -1065,10 +1065,269 @@
0,
};
+/* defaultdict type *********************************************************/
+
+typedef struct {
+ PyDictObject dict;
+ PyObject *default_factory;
+} defdictobject;
+
+static PyTypeObject defdict_type; /* Forward */
+
+PyDoc_STRVAR(defdict_missing_doc,
+"__missing__(key) # Called by __getitem__ for missing key; pseudo-code:\n\
+ if self.default_factory is None: raise KeyError(key)\n\
+ self[key] = value = self.default_factory()\n\
+ return value\n\
+");
+
+static PyObject *
+defdict_missing(defdictobject *dd, PyObject *key)
+{
+ PyObject *factory = dd->default_factory;
+ PyObject *value;
+ if (factory == NULL || factory == Py_None) {
+ /* XXX Call dict.__missing__(key) */
+ PyErr_SetObject(PyExc_KeyError, key);
+ return NULL;
+ }
+ value = PyEval_CallObject(factory, NULL);
+ if (value == NULL)
+ return value;
+ if (PyObject_SetItem((PyObject *)dd, key, value) < 0) {
+ Py_DECREF(value);
+ return NULL;
+ }
+ return value;
+}
+
+PyDoc_STRVAR(defdict_copy_doc, "D.copy() -> a shallow copy of D.");
+
+static PyObject *
+defdict_copy(defdictobject *dd)
+{
+ /* This calls the object's class. That only works for subclasses
+ whose class constructor has the same signature. Subclasses that
+ define a different constructor signature must override copy().
+ */
+ return PyObject_CallFunctionObjArgs((PyObject *)dd->dict.ob_type,
+ dd->default_factory, dd, NULL);
+}
+
+static PyObject *
+defdict_reduce(defdictobject *dd)
+{
+ /* __reduce__ must returns a 5-tuple as follows:
+
+ - factory function
+ - tuple of args for the factory function
+ - additional state (here None)
+ - sequence iterator (here None)
+ - dictionary iterator (yielding successive (key, value) pairs
+
+ This API is used by pickle.py and copy.py.
+
+ For this to be useful with pickle.py, the default_factory
+ must be picklable; e.g., None, a built-in, or a global
+ function in a module or package.
+
+ Both shallow and deep copying are supported, but for deep
+ copying, the default_factory must be deep-copyable; e.g. None,
+ or a built-in (functions are not copyable at this time).
+
+ This only works for subclasses as long as their constructor
+ signature is compatible; the first argument must be the
+ optional default_factory, defaulting to None.
+ */
+ PyObject *args;
+ PyObject *items;
+ PyObject *result;
+ if (dd->default_factory == NULL || dd->default_factory == Py_None)
+ args = PyTuple_New(0);
+ else
+ args = PyTuple_Pack(1, dd->default_factory);
+ if (args == NULL)
+ return NULL;
+ items = PyObject_CallMethod((PyObject *)dd, "iteritems", "()");
+ if (items == NULL) {
+ Py_DECREF(args);
+ return NULL;
+ }
+ result = PyTuple_Pack(5, dd->dict.ob_type, args,
+ Py_None, Py_None, items);
+ Py_DECREF(args);
+ return result;
+}
+
+static PyMethodDef defdict_methods[] = {
+ {"__missing__", (PyCFunction)defdict_missing, METH_O,
+ defdict_missing_doc},
+ {"copy", (PyCFunction)defdict_copy, METH_NOARGS,
+ defdict_copy_doc},
+ {"__copy__", (PyCFunction)defdict_copy, METH_NOARGS,
+ defdict_copy_doc},
+ {"__reduce__", (PyCFunction)defdict_reduce, METH_NOARGS,
+ reduce_doc},
+ {NULL}
+};
+
+static PyMemberDef defdict_members[] = {
+ {"default_factory", T_OBJECT,
+ offsetof(defdictobject, default_factory), 0,
+ PyDoc_STR("Factory for default value called by __missing__().")},
+ {NULL}
+};
+
+static void
+defdict_dealloc(defdictobject *dd)
+{
+ Py_CLEAR(dd->default_factory);
+ PyDict_Type.tp_dealloc((PyObject *)dd);
+}
+
+static int
+defdict_print(defdictobject *dd, FILE *fp, int flags)
+{
+ int sts;
+ fprintf(fp, "defaultdict(");
+ if (dd->default_factory == NULL)
+ fprintf(fp, "None");
+ else {
+ PyObject_Print(dd->default_factory, fp, 0);
+ }
+ fprintf(fp, ", ");
+ sts = PyDict_Type.tp_print((PyObject *)dd, fp, 0);
+ fprintf(fp, ")");
+ return sts;
+}
+
+static PyObject *
+defdict_repr(defdictobject *dd)
+{
+ PyObject *defrepr;
+ PyObject *baserepr;
+ PyObject *result;
+ baserepr = PyDict_Type.tp_repr((PyObject *)dd);
+ if (baserepr == NULL)
+ return NULL;
+ if (dd->default_factory == NULL)
+ defrepr = PyString_FromString("None");
+ else
+ defrepr = PyObject_Repr(dd->default_factory);
+ if (defrepr == NULL) {
+ Py_DECREF(baserepr);
+ return NULL;
+ }
+ result = PyString_FromFormat("defaultdict(%s, %s)",
+ PyString_AS_STRING(defrepr),
+ PyString_AS_STRING(baserepr));
+ Py_DECREF(defrepr);
+ Py_DECREF(baserepr);
+ return result;
+}
+
+static int
+defdict_traverse(PyObject *self, visitproc visit, void *arg)
+{
+ Py_VISIT(((defdictobject *)self)->default_factory);
+ return PyDict_Type.tp_traverse(self, visit, arg);
+}
+
+static int
+defdict_tp_clear(defdictobject *dd)
+{
+ if (dd->default_factory != NULL) {
+ Py_DECREF(dd->default_factory);
+ dd->default_factory = NULL;
+ }
+ return PyDict_Type.tp_clear((PyObject *)dd);
+}
+
+static int
+defdict_init(PyObject *self, PyObject *args, PyObject *kwds)
+{
+ defdictobject *dd = (defdictobject *)self;
+ PyObject *olddefault = dd->default_factory;
+ PyObject *newdefault = NULL;
+ PyObject *newargs;
+ int result;
+ if (args == NULL || !PyTuple_Check(args))
+ newargs = PyTuple_New(0);
+ else {
+ Py_ssize_t n = PyTuple_GET_SIZE(args);
+ if (n > 0)
+ newdefault = PyTuple_GET_ITEM(args, 0);
+ newargs = PySequence_GetSlice(args, 1, n);
+ }
+ if (newargs == NULL)
+ return -1;
+ Py_XINCREF(newdefault);
+ dd->default_factory = newdefault;
+ result = PyDict_Type.tp_init(self, newargs, kwds);
+ Py_DECREF(newargs);
+ Py_XDECREF(olddefault);
+ return result;
+}
+
+PyDoc_STRVAR(defdict_doc,
+"defaultdict(default_factory) --> dict with default factory\n\
+\n\
+The default factory is called without arguments to produce\n\
+a new value when a key is not present, in __getitem__ only.\n\
+A defaultdict compares equal to a dict with the same items.\n\
+");
+
+static PyTypeObject defdict_type = {
+ PyObject_HEAD_INIT(NULL)
+ 0, /* ob_size */
+ "collections.defaultdict", /* tp_name */
+ sizeof(defdictobject), /* tp_basicsize */
+ 0, /* tp_itemsize */
+ /* methods */
+ (destructor)defdict_dealloc, /* tp_dealloc */
+ (printfunc)defdict_print, /* tp_print */
+ 0, /* tp_getattr */
+ 0, /* tp_setattr */
+ 0, /* tp_compare */
+ (reprfunc)defdict_repr, /* tp_repr */
+ 0, /* tp_as_number */
+ 0, /* tp_as_sequence */
+ 0, /* tp_as_mapping */
+ 0, /* tp_hash */
+ 0, /* tp_call */
+ 0, /* tp_str */
+ PyObject_GenericGetAttr, /* tp_getattro */
+ 0, /* tp_setattro */
+ 0, /* tp_as_buffer */
+ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC |
+ Py_TPFLAGS_HAVE_WEAKREFS, /* tp_flags */
+ defdict_doc, /* tp_doc */
+ (traverseproc)defdict_traverse, /* tp_traverse */
+ (inquiry)defdict_tp_clear, /* tp_clear */
+ 0, /* tp_richcompare */
+ 0, /* tp_weaklistoffset*/
+ 0, /* tp_iter */
+ 0, /* tp_iternext */
+ defdict_methods, /* tp_methods */
+ defdict_members, /* tp_members */
+ 0, /* tp_getset */
+ &PyDict_Type, /* tp_base */
+ 0, /* tp_dict */
+ 0, /* tp_descr_get */
+ 0, /* tp_descr_set */
+ 0, /* tp_dictoffset */
+ (initproc)defdict_init, /* tp_init */
+ PyType_GenericAlloc, /* tp_alloc */
+ 0, /* tp_new */
+ PyObject_GC_Del, /* tp_free */
+};
+
/* module level code ********************************************************/
PyDoc_STRVAR(module_doc,
-"High performance data structures\n\
+"High performance data structures.\n\
+- deque: ordered collection accessible from endpoints only\n\
+- defaultdict: dict subclass with a default value factory\n\
");
PyMODINIT_FUNC
@@ -1085,6 +1344,11 @@
Py_INCREF(&deque_type);
PyModule_AddObject(m, "deque", (PyObject *)&deque_type);
+ if (PyType_Ready(&defdict_type) < 0)
+ return;
+ Py_INCREF(&defdict_type);
+ PyModule_AddObject(m, "defaultdict", (PyObject *)&defdict_type);
+
if (PyType_Ready(&dequeiter_type) < 0)
return;
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index f5e5320..2254762 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -882,8 +882,22 @@
return NULL;
}
v = (mp->ma_lookup)(mp, key, hash) -> me_value;
- if (v == NULL)
+ if (v == NULL) {
+ if (!PyDict_CheckExact(mp)) {
+ /* Look up __missing__ method if we're a subclass. */
+ static PyObject *missing_str = NULL;
+ if (missing_str == NULL)
+ missing_str =
+ PyString_InternFromString("__missing__");
+ PyObject *missing = _PyType_Lookup(mp->ob_type,
+ missing_str);
+ if (missing != NULL)
+ return PyObject_CallFunctionObjArgs(missing,
+ (PyObject *)mp, key, NULL);
+ }
PyErr_SetObject(PyExc_KeyError, key);
+ return NULL;
+ }
else
Py_INCREF(v);
return v;