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#1826: allow dotted attribute paths in operator.attrgetter.

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This commit is contained in:
Georg Brandl 2008-02-23 23:02:23 +00:00
parent b0b0317ba2
commit e2065c65d3
4 changed files with 78 additions and 5 deletions
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51
Modules/operator.c
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@ -495,6 +495,49 @@ attrgetter_traverse(attrgetterobject *ag, visitproc visit, void *arg)
return 0;
}
static PyObject *
dotted_getattr(PyObject *obj, PyObject *attr)
{
char *s, *p;
#ifdef Py_USING_UNICODE
if (PyUnicode_Check(attr)) {
attr = _PyUnicode_AsDefaultEncodedString(attr, NULL);
if (attr == NULL)
return NULL;
}
#endif
if (!PyString_Check(attr)) {
PyErr_SetString(PyExc_TypeError,
"attribute name must be a string");
return NULL;
}
s = PyString_AS_STRING(attr);
Py_INCREF(obj);
for (;;) {
PyObject *newobj, *str;
p = strchr(s, '.');
str = p ? PyString_FromStringAndSize(s, (p-s)) :
PyString_FromString(s);
if (str == NULL) {
Py_DECREF(obj);
return NULL;
}
newobj = PyObject_GetAttr(obj, str);
Py_DECREF(str);
Py_DECREF(obj);
if (newobj == NULL)
return NULL;
obj = newobj;
if (p == NULL) break;
s = p+1;
}
return obj;
}
static PyObject *
attrgetter_call(attrgetterobject *ag, PyObject *args, PyObject *kw)
{
@ -504,7 +547,7 @@ attrgetter_call(attrgetterobject *ag, PyObject *args, PyObject *kw)
if (!PyArg_UnpackTuple(args, "attrgetter", 1, 1, &obj))
return NULL;
if (ag->nattrs == 1)
return PyObject_GetAttr(obj, ag->attr);
return dotted_getattr(obj, ag->attr);
assert(PyTuple_Check(ag->attr));
assert(PyTuple_GET_SIZE(ag->attr) == nattrs);
@ -516,7 +559,7 @@ attrgetter_call(attrgetterobject *ag, PyObject *args, PyObject *kw)
for (i=0 ; i < nattrs ; i++) {
PyObject *attr, *val;
attr = PyTuple_GET_ITEM(ag->attr, i);
val = PyObject_GetAttr(obj, attr);
val = dotted_getattr(obj, attr);
if (val == NULL) {
Py_DECREF(result);
return NULL;
@ -531,7 +574,9 @@ PyDoc_STRVAR(attrgetter_doc,
\n\
Return a callable object that fetches the given attribute(s) from its operand.\n\
After, f=attrgetter('name'), the call f(r) returns r.name.\n\
After, g=attrgetter('name', 'date'), the call g(r) returns (r.name, r.date).");
After, g=attrgetter('name', 'date'), the call g(r) returns (r.name, r.date).\n\
After, h=attrgetter('name.first', 'name.last'), the call h(r) returns\n\
(r.name.first, r.name.last).");
static PyTypeObject attrgetter_type = {
PyVarObject_HEAD_INIT(NULL, 0)