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Implement PEP 3115 -- new metaclass syntax and semantics.

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The compiler package hasn't been updated yet; test_compiler.py fails.
Otherwise all tests seem to be passing now.  There are no occurrences
of __metaclass__ left in the standard library.
Docs have not been updated.
This commit is contained in:
Guido van Rossum 2007-03-18 15:41:51 +00:00
parent ef17c16b36
commit 52cc1d838f
25 changed files with 604 additions and 237 deletions
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109
Python/bltinmodule.c
View file

@ -30,6 +30,113 @@ static PyObject *filterunicode(PyObject *, PyObject *);
#endif
static PyObject *filtertuple (PyObject *, PyObject *);
static PyObject *
builtin___build_class__(PyObject *self, PyObject *args, PyObject *kwds)
{
PyObject *func, *name, *bases, *mkw, *meta, *prep, *ns, *res;
Py_ssize_t nargs, nbases;
assert(args != NULL);
if (!PyTuple_Check(args)) {
PyErr_SetString(PyExc_TypeError,
"__build_class__: args is not a tuple");
return NULL;
}
nargs = PyTuple_GET_SIZE(args);
if (nargs < 2) {
PyErr_SetString(PyExc_TypeError,
"__build_class__: not enough arguments");
return NULL;
}
func = PyTuple_GET_ITEM(args, 0); /* Better be callable */
name = PyTuple_GET_ITEM(args, 1);
if (!PyString_Check(name)) {
PyErr_SetString(PyExc_TypeError,
"__build_class__: name is not a string");
return NULL;
}
bases = PyTuple_GetSlice(args, 2, nargs);
if (bases == NULL)
return NULL;
nbases = nargs - 2;
if (kwds == NULL) {
meta = NULL;
mkw = NULL;
}
else {
mkw = PyDict_Copy(kwds); /* Don't modify kwds passed in! */
if (mkw == NULL) {
Py_DECREF(bases);
return NULL;
}
meta = PyDict_GetItemString(mkw, "metaclass");
if (meta != NULL) {
Py_INCREF(meta);
if (PyDict_DelItemString(mkw, "metaclass") < 0) {
Py_DECREF(meta);
Py_DECREF(mkw);
Py_DECREF(bases);
return NULL;
}
}
}
if (meta == NULL) {
if (PyTuple_GET_SIZE(bases) == 0)
meta = (PyObject *) (&PyType_Type);
else {
PyObject *base0 = PyTuple_GET_ITEM(bases, 0);
meta = (PyObject *) (base0->ob_type);
}
Py_INCREF(meta);
}
prep = PyObject_GetAttrString(meta, "__prepare__");
if (prep == NULL) {
PyErr_Clear();
ns = PyDict_New();
}
else {
PyObject *pargs = Py_BuildValue("OO", name, bases);
if (pargs == NULL) {
Py_DECREF(prep);
Py_DECREF(meta);
Py_XDECREF(mkw);
Py_DECREF(bases);
return NULL;
}
ns = PyEval_CallObjectWithKeywords(prep, pargs, mkw);
Py_DECREF(pargs);
Py_DECREF(prep);
if (ns == NULL) {
Py_DECREF(meta);
Py_XDECREF(mkw);
Py_DECREF(bases);
return NULL;
}
}
res = PyObject_CallFunctionObjArgs(func, ns, NULL);
if (res != NULL) {
PyObject *margs;
Py_DECREF(res);
res = NULL;
margs = Py_BuildValue("OOO", name, bases, ns);
if (margs != NULL) {
res = PyEval_CallObjectWithKeywords(meta, margs, mkw);
Py_DECREF(margs);
}
}
Py_DECREF(ns);
Py_DECREF(meta);
Py_XDECREF(mkw);
Py_DECREF(bases);
return res;
}
PyDoc_STRVAR(build_class_doc,
"__build_class__(func, name, *bases, metaclass=None, **kwds) -> class\n\
\n\
Internal helper function used by the class statement.");
static PyObject *
builtin___import__(PyObject *self, PyObject *args, PyObject *kwds)
{
@ -2103,6 +2210,8 @@ NOTE: This is implemented using itertools.izip().");
static PyMethodDef builtin_methods[] = {
{"__build_class__", (PyCFunction)builtin___build_class__,
METH_VARARGS | METH_KEYWORDS, build_class_doc},
{"__import__", (PyCFunction)builtin___import__, METH_VARARGS | METH_KEYWORDS, import_doc},
{"abs", builtin_abs, METH_O, abs_doc},
{"all", builtin_all, METH_O, all_doc},