Index: Modules/_pickle.c
===================================================================
--- Modules/_pickle.c	(revision 65456)
+++ Modules/_pickle.c	(working copy)
@@ -316,6 +316,8 @@
                                    objects. */
     int fast_nesting;
     PyObject *fast_memo;
+    PyObject *dispatch;         /* Dispatch dictionary, used to extend or
+                                   modify Pickler. */
 } PicklerObject;
 
 typedef struct UnpicklerObject {
@@ -2089,6 +2091,30 @@
 
     type = Py_TYPE(obj);
 
+    /* Mimic the dispatch dictionary in the Python implementation of Pickler.
+       This check should be done first to allows the pickling process of
+       built-in types to be overridden (like in pickle.py).  */
+    reduce_func = PyDict_GetItemWithError(self->dispatch, (PyObject *)type);
+    if (reduce_func != NULL) {
+        /* Here, the reference count of reduce_func is increased to
+           allow the blind DECREF at the end of the save() routine. */
+        Py_INCREF(reduce_func);
+        /* reduce_value is unused and should be Py_None.
+           XXX: Perhaps a warning should be issued if reduce_value
+           is not Py_None? */
+        reduce_value = PyObject_CallFunctionObjArgs(reduce_func,
+                                                    (PyObject *)self,
+                                                    obj,
+                                                    NULL);
+        if (reduce_value == NULL)
+            goto error;
+        else
+            goto done;
+    }
+    else if (PyErr_Occurred()) {
+        goto error;
+    }
+
     /* XXX: The old cPickle had an optimization that used switch-case
        statement dispatching on the first letter of the type name. It was
        probably not a bad idea after all. If benchmarks shows that particular
@@ -2349,6 +2375,7 @@
     Py_XDECREF(self->pers_func);
     Py_XDECREF(self->arg);
     Py_XDECREF(self->fast_memo);
+    Py_XDECREF(self->dispatch);
 
     PyMem_Free(self->write_buf);
 
@@ -2363,6 +2390,7 @@
     Py_VISIT(self->pers_func);
     Py_VISIT(self->arg);
     Py_VISIT(self->fast_memo);
+    Py_VISIT(self->dispatch);
     return 0;
 }
 
@@ -2374,6 +2402,7 @@
     Py_CLEAR(self->pers_func);
     Py_CLEAR(self->arg);
     Py_CLEAR(self->fast_memo);
+    Py_CLEAR(self->dispatch);
 
     PyMem_Free(self->write_buf);
     self->write_buf = NULL;
@@ -2461,6 +2490,9 @@
     self->memo = PyDict_New();
     if (self->memo == NULL)
         return -1;
+    self->dispatch = PyDict_New();
+    if (self->dispatch == NULL)
+        return -1;
 
     return 0;
 }
@@ -2499,6 +2531,16 @@
 }
 
 static PyObject *
+Pickler_get_dispatch(PicklerObject *self)
+{
+    if (self->dispatch == NULL)
+        PyErr_SetString(PyExc_AttributeError, "dispatch");
+    else
+        Py_INCREF(self->dispatch);
+    return self->dispatch;
+}
+
+static PyObject *
 Pickler_get_persid(PicklerObject *self)
 {
     if (self->pers_func == NULL)
@@ -2539,10 +2581,12 @@
 };
 
 static PyGetSetDef Pickler_getsets[] = {
+    {"dispatch",      (getter)Pickler_get_dispatch, NULL},
     {"memo",          (getter)Pickler_get_memo,
                       (setter)Pickler_set_memo},
     {"persistent_id", (getter)Pickler_get_persid,
                       (setter)Pickler_set_persid},
+
     {NULL}
 };