Make functional.partial() more closely match the spec by emulating

some useful features of regular functions:

* Made weak referencable.
* Allow attribute access so a user can set __name__, __doc__, etc.

diff --git a/Lib/test/test_functional.py b/Lib/test/test_functional.py
index db3a289f99d89a3b540de5cbd9caf4ed1537b492..8f19d6b2ae454811939c83c9662fea1ae474daeb 100644 (file)
--- a/Lib/test/test_functional.py
+++ b/Lib/test/test_functional.py
@@ -1,6 +1,7 @@
 import functional
 import unittest
 from test import test_support
+from weakref import proxy
 
 @staticmethod
 def PythonPartial(func, *args, **keywords):
@@ -116,6 +117,22 @@ class TestPartial(unittest.TestCase):
         self.assertRaises(ZeroDivisionError, self.thetype(f), 1, 0)
         self.assertRaises(ZeroDivisionError, self.thetype(f, y=0), 1)
 
+    def test_attributes(self):
+        p = self.thetype(hex)
+        try:
+            del p.__dict__
+        except TypeError:
+            pass
+        else:
+            self.fail('partial object allowed __dict__ to be deleted')
+
+    def test_weakref(self):
+        f = self.thetype(int, base=16)
+        p = proxy(f)
+        self.assertEqual(f.func, p.func)
+        f = None
+        self.assertRaises(ReferenceError, getattr, p, 'func')
+
 
 class PartialSubclass(functional.partial):
     pass

diff --git a/Modules/functionalmodule.c b/Modules/functionalmodule.c
index 18efab20602f3b5ec04471346a1d63ee8a824099..95ffd5dde9cc2928ef81a09f8cf9093bb4583472 100644 (file)
--- a/Modules/functionalmodule.c
+++ b/Modules/functionalmodule.c
@@ -16,6 +16,8 @@ typedef struct {
        PyObject *fn;
        PyObject *args;
        PyObject *kw;
+       PyObject *dict;
+       PyObject *weakreflist; /* List of weak references */
 } partialobject;
 
 static PyTypeObject partial_type;
@@ -63,6 +65,9 @@ partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
                Py_INCREF(Py_None);
        }
 
+       pto->weakreflist = NULL;
+       pto->dict = NULL;
+
        return (PyObject *)pto;
 }
 
@@ -70,9 +75,12 @@ static void
 partial_dealloc(partialobject *pto)
 {
        PyObject_GC_UnTrack(pto);
+       if (pto->weakreflist != NULL)
+               PyObject_ClearWeakRefs((PyObject *) pto);
        Py_XDECREF(pto->fn);
        Py_XDECREF(pto->args);
        Py_XDECREF(pto->kw);
+       Py_XDECREF(pto->dict);
        pto->ob_type->tp_free(pto);
 }
 
@@ -128,6 +136,7 @@ partial_traverse(partialobject *pto, visitproc visit, void *arg)
        Py_VISIT(pto->fn);
        Py_VISIT(pto->args);
        Py_VISIT(pto->kw);
+       Py_VISIT(pto->dict);
        return 0;
 }
 
@@ -146,6 +155,47 @@ static PyMemberDef partial_memberlist[] = {
        {NULL}  /* Sentinel */
 };
 
+static PyObject *
+partial_get_dict(partialobject *pto)
+{
+       if (pto->dict == NULL) {
+               pto->dict = PyDict_New();
+               if (pto->dict == NULL)
+                       return NULL;
+       }
+       Py_INCREF(pto->dict);
+       return pto->dict;
+}
+
+static int
+partial_set_dict(partialobject *pto, PyObject *value)
+{
+       PyObject *tmp;
+
+       /* It is illegal to del p.__dict__ */
+       if (value == NULL) {
+               PyErr_SetString(PyExc_TypeError,
+                               "a partial object's dictionary may not be deleted");
+               return -1;
+       }
+       /* Can only set __dict__ to a dictionary */
+       if (!PyDict_Check(value)) {
+               PyErr_SetString(PyExc_TypeError,
+                               "setting partial object's dictionary to a non-dict");
+               return -1;
+       }
+       tmp = pto->dict;
+       Py_INCREF(value);
+       pto->dict = value;
+       Py_XDECREF(tmp);
+       return 0;
+}
+
+static PyGetSetDef partail_getsetlist[] = {
+       {"__dict__", (getter)partial_get_dict, (setter)partial_set_dict},
+       {NULL} /* Sentinel */
+};
+
 static PyTypeObject partial_type = {
        PyObject_HEAD_INIT(NULL)
        0,                              /* ob_size */
@@ -166,25 +216,25 @@ static PyTypeObject partial_type = {
        (ternaryfunc)partial_call,      /* tp_call */
        0,                              /* tp_str */
        PyObject_GenericGetAttr,        /* tp_getattro */
-       0,                              /* tp_setattro */
+       PyObject_GenericSetAttr,        /* tp_setattro */
        0,                              /* tp_as_buffer */
        Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-               Py_TPFLAGS_BASETYPE,    /* tp_flags */
+               Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_WEAKREFS, /* tp_flags */
        partial_doc,                    /* tp_doc */
        (traverseproc)partial_traverse, /* tp_traverse */
        0,                              /* tp_clear */
        0,                              /* tp_richcompare */
-       0,                              /* tp_weaklistoffset */
+       offsetof(partialobject, weakreflist),   /* tp_weaklistoffset */
        0,                              /* tp_iter */
        0,                              /* tp_iternext */
        0,                              /* tp_methods */
        partial_memberlist,             /* tp_members */
-       0,                              /* tp_getset */
+       partail_getsetlist,             /* tp_getset */
        0,                              /* tp_base */
        0,                              /* tp_dict */
        0,                              /* tp_descr_get */
        0,                              /* tp_descr_set */
-       0,                              /* tp_dictoffset */
+       offsetof(partialobject, dict),  /* tp_dictoffset */
        0,                              /* tp_init */
        0,                              /* tp_alloc */
        partial_new,                    /* tp_new */