Backport PEP 3141 from the py3k branch to the trunk. This includes r50877 (just
the complex_pow part), r56649, r56652, r56715, r57296, r57302, r57359, r57361,
r57372, r57738, r57739, r58017, r58039, r58040, and r59390, and new
documentation. The only significant difference is that round(x) returns a float
to preserve backward-compatibility. See http://bugs.python.org/issue1689.
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 5d0b920..574b96a 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -986,9 +986,10 @@
* bugs so we have to figure it out ourselves.
*/
if (iw != floor(iw)) {
- PyErr_SetString(PyExc_ValueError, "negative number "
- "cannot be raised to a fractional power");
- return NULL;
+ /* Negative numbers raised to fractional powers
+ * become complex.
+ */
+ return PyComplex_Type.tp_as_number->nb_power(v, w, z);
}
/* iw is an exact integer, albeit perhaps a very large one.
* -1 raised to an exact integer should never be exceptional.
@@ -1035,17 +1036,6 @@
}
static PyObject *
-float_pos(PyFloatObject *v)
-{
- if (PyFloat_CheckExact(v)) {
- Py_INCREF(v);
- return (PyObject *)v;
- }
- else
- return PyFloat_FromDouble(v->ob_fval);
-}
-
-static PyObject *
float_abs(PyFloatObject *v)
{
return PyFloat_FromDouble(fabs(v->ob_fval));
@@ -1083,14 +1073,7 @@
}
static PyObject *
-float_long(PyObject *v)
-{
- double x = PyFloat_AsDouble(v);
- return PyLong_FromDouble(x);
-}
-
-static PyObject *
-float_int(PyObject *v)
+float_trunc(PyObject *v)
{
double x = PyFloat_AsDouble(v);
double wholepart; /* integral portion of x, rounded toward 0 */
@@ -1116,6 +1099,54 @@
}
static PyObject *
+float_round(PyObject *v, PyObject *args)
+{
+#define UNDEF_NDIGITS (-0x7fffffff) /* Unlikely ndigits value */
+ double x;
+ double f;
+ double flr, cil;
+ double rounded;
+ int i;
+ int ndigits = UNDEF_NDIGITS;
+
+ if (!PyArg_ParseTuple(args, "|i", &ndigits))
+ return NULL;
+
+ x = PyFloat_AsDouble(v);
+
+ if (ndigits != UNDEF_NDIGITS) {
+ f = 1.0;
+ i = abs(ndigits);
+ while (--i >= 0)
+ f = f*10.0;
+ if (ndigits < 0)
+ x /= f;
+ else
+ x *= f;
+ }
+
+ flr = floor(x);
+ cil = ceil(x);
+
+ if (x-flr > 0.5)
+ rounded = cil;
+ else if (x-flr == 0.5)
+ rounded = fmod(flr, 2) == 0 ? flr : cil;
+ else
+ rounded = flr;
+
+ if (ndigits != UNDEF_NDIGITS) {
+ if (ndigits < 0)
+ rounded *= f;
+ else
+ rounded /= f;
+ }
+
+ return PyFloat_FromDouble(rounded);
+#undef UNDEF_NDIGITS
+}
+
+static PyObject *
float_float(PyObject *v)
{
if (PyFloat_CheckExact(v))
@@ -1302,7 +1333,20 @@
"Overrides the automatic determination of C-level floating point type.\n"
"This affects how floats are converted to and from binary strings.");
+static PyObject *
+float_getzero(PyObject *v, void *closure)
+{
+ return PyFloat_FromDouble(0.0);
+}
+
static PyMethodDef float_methods[] = {
+ {"conjugate", (PyCFunction)float_float, METH_NOARGS,
+ "Returns self, the complex conjugate of any float."},
+ {"__trunc__", (PyCFunction)float_trunc, METH_NOARGS,
+ "Returns the Integral closest to x between 0 and x."},
+ {"__round__", (PyCFunction)float_round, METH_VARARGS,
+ "Returns the Integral closest to x, rounding half toward even.\n"
+ "When an argument is passed, works like built-in round(x, ndigits)."},
{"__getnewargs__", (PyCFunction)float_getnewargs, METH_NOARGS},
{"__getformat__", (PyCFunction)float_getformat,
METH_O|METH_CLASS, float_getformat_doc},
@@ -1311,6 +1355,18 @@
{NULL, NULL} /* sentinel */
};
+static PyGetSetDef float_getset[] = {
+ {"real",
+ (getter)float_float, (setter)NULL,
+ "the real part of a complex number",
+ NULL},
+ {"imag",
+ (getter)float_getzero, (setter)NULL,
+ "the imaginary part of a complex number",
+ NULL},
+ {NULL} /* Sentinel */
+};
+
PyDoc_STRVAR(float_doc,
"float(x) -> floating point number\n\
\n\
@@ -1326,7 +1382,7 @@
float_divmod, /*nb_divmod*/
float_pow, /*nb_power*/
(unaryfunc)float_neg, /*nb_negative*/
- (unaryfunc)float_pos, /*nb_positive*/
+ (unaryfunc)float_float, /*nb_positive*/
(unaryfunc)float_abs, /*nb_absolute*/
(inquiry)float_nonzero, /*nb_nonzero*/
0, /*nb_invert*/
@@ -1336,8 +1392,8 @@
0, /*nb_xor*/
0, /*nb_or*/
float_coerce, /*nb_coerce*/
- float_int, /*nb_int*/
- float_long, /*nb_long*/
+ float_trunc, /*nb_int*/
+ float_trunc, /*nb_long*/
float_float, /*nb_float*/
0, /* nb_oct */
0, /* nb_hex */
@@ -1389,7 +1445,7 @@
0, /* tp_iternext */
float_methods, /* tp_methods */
0, /* tp_members */
- 0, /* tp_getset */
+ float_getset, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */