cpython/Modules/functionalmodule.c

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#include "Python.h"
#include "structmember.h"
/* Functional module written and maintained
by Hye-Shik Chang <perky@FreeBSD.org>
with adaptations by Raymond Hettinger <python@rcn.com>
Copyright (c) 2004, 2005 Python Software Foundation.
All rights reserved.
*/
/* partial object **********************************************************/
typedef struct {
PyObject_HEAD
PyObject *fn;
PyObject *args;
PyObject *kw;
PyObject *dict;
PyObject *weakreflist; /* List of weak references */
} partialobject;
static PyTypeObject partial_type;
static PyObject *
partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
{
PyObject *func;
partialobject *pto;
if (PyTuple_GET_SIZE(args) < 1) {
PyErr_SetString(PyExc_TypeError,
"type 'partial' takes at least one argument");
return NULL;
}
func = PyTuple_GET_ITEM(args, 0);
if (!PyCallable_Check(func)) {
PyErr_SetString(PyExc_TypeError,
"the first argument must be callable");
return NULL;
}
/* create partialobject structure */
pto = (partialobject *)type->tp_alloc(type, 0);
if (pto == NULL)
return NULL;
pto->fn = func;
Py_INCREF(func);
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pto->args = PyTuple_GetSlice(args, 1, PY_SSIZE_T_MAX);
if (pto->args == NULL) {
pto->kw = NULL;
Py_DECREF(pto);
return NULL;
}
if (kw != NULL) {
pto->kw = PyDict_Copy(kw);
if (pto->kw == NULL) {
Py_DECREF(pto);
return NULL;
}
} else {
pto->kw = Py_None;
Py_INCREF(Py_None);
}
pto->weakreflist = NULL;
pto->dict = NULL;
return (PyObject *)pto;
}
static void
partial_dealloc(partialobject *pto)
{
PyObject_GC_UnTrack(pto);
if (pto->weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *) pto);
Py_XDECREF(pto->fn);
Py_XDECREF(pto->args);
Py_XDECREF(pto->kw);
Py_XDECREF(pto->dict);
pto->ob_type->tp_free(pto);
}
static PyObject *
partial_call(partialobject *pto, PyObject *args, PyObject *kw)
{
PyObject *ret;
PyObject *argappl = NULL, *kwappl = NULL;
assert (PyCallable_Check(pto->fn));
assert (PyTuple_Check(pto->args));
assert (pto->kw == Py_None || PyDict_Check(pto->kw));
if (PyTuple_GET_SIZE(pto->args) == 0) {
argappl = args;
Py_INCREF(args);
} else if (PyTuple_GET_SIZE(args) == 0) {
argappl = pto->args;
Py_INCREF(pto->args);
} else {
argappl = PySequence_Concat(pto->args, args);
if (argappl == NULL)
return NULL;
}
if (pto->kw == Py_None) {
kwappl = kw;
Py_XINCREF(kw);
} else {
kwappl = PyDict_Copy(pto->kw);
if (kwappl == NULL) {
Py_DECREF(argappl);
return NULL;
}
if (kw != NULL) {
if (PyDict_Merge(kwappl, kw, 1) != 0) {
Py_DECREF(argappl);
Py_DECREF(kwappl);
return NULL;
}
}
}
ret = PyObject_Call(pto->fn, argappl, kwappl);
Py_DECREF(argappl);
Py_XDECREF(kwappl);
return ret;
}
static int
partial_traverse(partialobject *pto, visitproc visit, void *arg)
{
Py_VISIT(pto->fn);
Py_VISIT(pto->args);
Py_VISIT(pto->kw);
Py_VISIT(pto->dict);
return 0;
}
PyDoc_STRVAR(partial_doc,
"partial(func, *args, **keywords) - new function with partial application\n\
of the given arguments and keywords.\n");
#define OFF(x) offsetof(partialobject, x)
static PyMemberDef partial_memberlist[] = {
{"func", T_OBJECT, OFF(fn), READONLY,
"function object to use in future partial calls"},
{"args", T_OBJECT, OFF(args), READONLY,
"tuple of arguments to future partial calls"},
{"keywords", T_OBJECT, OFF(kw), READONLY,
"dictionary of keyword arguments to future partial calls"},
{NULL} /* Sentinel */
};
static PyObject *
partial_get_dict(partialobject *pto)
{
if (pto->dict == NULL) {
pto->dict = PyDict_New();
if (pto->dict == NULL)
return NULL;
}
Py_INCREF(pto->dict);
return pto->dict;
}
static int
partial_set_dict(partialobject *pto, PyObject *value)
{
PyObject *tmp;
/* It is illegal to del p.__dict__ */
if (value == NULL) {
PyErr_SetString(PyExc_TypeError,
"a partial object's dictionary may not be deleted");
return -1;
}
/* Can only set __dict__ to a dictionary */
if (!PyDict_Check(value)) {
PyErr_SetString(PyExc_TypeError,
"setting partial object's dictionary to a non-dict");
return -1;
}
tmp = pto->dict;
Py_INCREF(value);
pto->dict = value;
Py_XDECREF(tmp);
return 0;
}
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static PyGetSetDef partial_getsetlist[] = {
{"__dict__", (getter)partial_get_dict, (setter)partial_set_dict},
{NULL} /* Sentinel */
};
static PyTypeObject partial_type = {
PyObject_HEAD_INIT(NULL)
0, /* ob_size */
"functional.partial", /* tp_name */
sizeof(partialobject), /* tp_basicsize */
0, /* tp_itemsize */
/* methods */
(destructor)partial_dealloc, /* tp_dealloc */
0, /* tp_print */
0, /* tp_getattr */
0, /* tp_setattr */
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
(ternaryfunc)partial_call, /* tp_call */
0, /* tp_str */
PyObject_GenericGetAttr, /* tp_getattro */
PyObject_GenericSetAttr, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_WEAKREFS, /* tp_flags */
partial_doc, /* tp_doc */
(traverseproc)partial_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
offsetof(partialobject, weakreflist), /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
partial_memberlist, /* tp_members */
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partial_getsetlist, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */
0, /* tp_descr_set */
offsetof(partialobject, dict), /* tp_dictoffset */
0, /* tp_init */
0, /* tp_alloc */
partial_new, /* tp_new */
PyObject_GC_Del, /* tp_free */
};
/* module level code ********************************************************/
PyDoc_STRVAR(module_doc,
"Tools for functional programming.");
static PyMethodDef module_methods[] = {
{NULL, NULL} /* sentinel */
};
PyMODINIT_FUNC
initfunctional(void)
{
int i;
PyObject *m;
char *name;
PyTypeObject *typelist[] = {
&partial_type,
NULL
};
m = Py_InitModule3("functional", module_methods, module_doc);
if (m == NULL)
return;
for (i=0 ; typelist[i] != NULL ; i++) {
if (PyType_Ready(typelist[i]) < 0)
return;
name = strchr(typelist[i]->tp_name, '.');
assert (name != NULL);
Py_INCREF(typelist[i]);
PyModule_AddObject(m, name+1, (PyObject *)typelist[i]);
}
}