mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-03 16:39:00 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

Teach the UNPACK_SEQUENCE opcode how to tease an iterable object into

Browse source 
giving up the goods.
NEEDS DOC CHANGES
This commit is contained in:
Tim Peters 2001-06-21 02:49:55 +00:00
parent 2b13ce8317
commit d6d010b874
3 changed files with 93 additions and 32 deletions
Download patch file Download diff file Expand all files Collapse all files

70
Python/ceval.c
View file

@ -476,7 +476,7 @@ enum why_code {
};
static enum why_code do_raise(PyObject *, PyObject *, PyObject *);
static int unpack_sequence(PyObject *, int, PyObject **);
static int unpack_iterable(PyObject *, int, PyObject **);
PyObject *
@ -1488,18 +1488,11 @@ eval_frame(PyFrameObject *f)
}
}
}
else if (PySequence_Check(v)) {
if (unpack_sequence(v, oparg,
stack_pointer + oparg))
stack_pointer += oparg;
else
why = WHY_EXCEPTION;
}
else {
PyErr_SetString(PyExc_TypeError,
"unpack non-sequence");
else if (unpack_iterable(v, oparg,
stack_pointer + oparg))
stack_pointer += oparg;
else
why = WHY_EXCEPTION;
}
Py_DECREF(v);
break;
@ -2694,37 +2687,50 @@ do_raise(PyObject *type, PyObject *value, PyObject *tb)
return WHY_EXCEPTION;
}
/* Iterate v argcnt times and store the results on the stack (via decreasing
sp). Return 1 for success, 0 if error. */
static int
unpack_sequence(PyObject *v, int argcnt, PyObject **sp)
unpack_iterable(PyObject *v, int argcnt, PyObject **sp)
{
int i;
int i = 0;
PyObject *it; /* iter(v) */
PyObject *w;
for (i = 0; i < argcnt; i++) {
if (! (w = PySequence_GetItem(v, i))) {
if (PyErr_ExceptionMatches(PyExc_IndexError))
PyErr_SetString(PyExc_ValueError,
"unpack sequence of wrong size");
goto finally;
assert(v != NULL);
it = PyObject_GetIter(v);
if (it == NULL)
goto Error;
for (; i < argcnt; i++) {
w = PyIter_Next(it);
if (w == NULL) {
/* Iterator done, via error or exhaustion. */
if (!PyErr_Occurred()) {
PyErr_Format(PyExc_ValueError,
"need more than %d value%s to unpack",
i, i == 1 ? "" : "s");
}
goto Error;
}
*--sp = w;
}
/* we better get an IndexError now */
if (PySequence_GetItem(v, i) == NULL) {
if (PyErr_ExceptionMatches(PyExc_IndexError)) {
PyErr_Clear();
return 1;
}
/* some other exception occurred. fall through to finally */
/* We better have exhausted the iterator now. */
w = PyIter_Next(it);
if (w == NULL) {
if (PyErr_Occurred())
goto Error;
Py_DECREF(it);
return 1;
}
else
PyErr_SetString(PyExc_ValueError,
"unpack sequence of wrong size");
PyErr_SetString(PyExc_ValueError, "too many values to unpack");
/* fall through */
finally:
Error:
for (; i > 0; i--, sp++)
Py_DECREF(*sp);
Py_XDECREF(it);
return 0;
}