Both PEP 201 Lockstep Iteration and SF patch #101030 have been

accepted by the BDFL.

builtin_zip(): New function to implement the zip() function described
in the above proposal.

zip_doc[]: Docstring for zip().

builtin_methods[]: added entry for zip()

diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index fd587a093ccf3efb97f4e31152cfe2fe8cf552dc..6c2c3c70c9cba5db021ced6dbc4751ded751ff80 100644 (file)
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2150,6 +2150,61 @@ static char issubclass_doc[] =
 Return whether class C is a subclass (i.e., a derived class) of class B.";
 
 
+static PyObject*
+builtin_zip(PyObject *self, PyObject *args)
+{
+       PyObject *ret;
+       int itemsize = PySequence_Length(args);
+       int i, j;
+
+       if (itemsize < 1) {
+               PyErr_SetString(PyExc_TypeError,
+                               "at least one sequence is required");
+               return NULL;
+       }
+       /* args must be a tuple */
+       assert(PyTuple_Check(args));
+
+       if ((ret = PyList_New(0)) == NULL)
+               return NULL;
+
+       for (i = 0;; i++) {
+               PyObject *next = PyTuple_New(itemsize);
+               if (!next) {
+                       Py_DECREF(ret);
+                       return NULL;
+               }
+               for (j = 0; j < itemsize; j++) {
+                       PyObject *seq = PyTuple_GET_ITEM(args, j);
+                       PyObject *item = PySequence_GetItem(seq, i);
+
+                       if (!item) {
+                               if (PyErr_ExceptionMatches(PyExc_IndexError)) {
+                                       PyErr_Clear();
+                                       Py_DECREF(next);
+                                       return ret;
+                               }
+                               Py_DECREF(next);
+                               Py_DECREF(ret);
+                               return NULL;
+                       }
+                       PyTuple_SET_ITEM(next, j, item);
+               }
+               PyList_Append(ret, next);
+               Py_DECREF(next);
+       }
+       /* no return */
+}
+
+
+static char zip_doc[] =
+"zip(seq1 [, seq2 [...]]) -> [(seq1[0], seq2[0] ...), (...)]\n\
+\n\
+Return a list of tuples, where each tuple contains the i-th element\n\
+from each of the argument sequences.  The returned list is truncated\n\
+in length to the length of the shortest argument sequence.";
+
+
 static PyMethodDef builtin_methods[] = {
        {"__import__",  builtin___import__, 1, import_doc},
        {"abs",         builtin_abs, 1, abs_doc},
@@ -2207,6 +2262,7 @@ static PyMethodDef builtin_methods[] = {
        {"unichr",      builtin_unichr, 1, unichr_doc},
        {"vars",        builtin_vars, 1, vars_doc},
        {"xrange",      builtin_xrange, 1, xrange_doc},
+       {"zip",         builtin_zip, 1, zip_doc},
        {NULL,          NULL},
 };