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Viewing changes to Modules/_functoolsmodule.c

  • Committer: Jeffrey C. "The TimeHorse" Jacobs
  • Date: 2008-09-22 21:39:45 UTC
  • mfrom: (39055.1.33 Regexp-2.7)
  • Revision ID: darklord@timehorse.com-20080922213945-23717m5eiqpamcyn
Merged in changes from the Single-Loop Engine branch.

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Lines of Context:
Modules/_functoolsmodule.c
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   All rights reserved.
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*/
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/* reduce() *************************************************************/
 
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static PyObject *
 
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functools_reduce(PyObject *self, PyObject *args)
 
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{
 
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        PyObject *seq, *func, *result = NULL, *it;
 
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        if (!PyArg_UnpackTuple(args, "reduce", 2, 3, &func, &seq, &result))
 
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                return NULL;
 
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        if (result != NULL)
 
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                Py_INCREF(result);
 
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        it = PyObject_GetIter(seq);
 
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        if (it == NULL) {
 
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                PyErr_SetString(PyExc_TypeError,
 
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                    "reduce() arg 2 must support iteration");
 
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                Py_XDECREF(result);
 
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                return NULL;
 
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        }
 
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        if ((args = PyTuple_New(2)) == NULL)
 
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                goto Fail;
 
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        for (;;) {
 
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                PyObject *op2;
 
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                if (args->ob_refcnt > 1) {
 
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                        Py_DECREF(args);
 
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                        if ((args = PyTuple_New(2)) == NULL)
 
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                                goto Fail;
 
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                }
 
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                op2 = PyIter_Next(it);
 
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                if (op2 == NULL) {
 
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                        if (PyErr_Occurred())
 
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                                goto Fail;
 
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                        break;
 
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                }
 
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                if (result == NULL)
 
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                        result = op2;
 
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                else {
 
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                        PyTuple_SetItem(args, 0, result);
 
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                        PyTuple_SetItem(args, 1, op2);
 
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                        if ((result = PyEval_CallObject(func, args)) == NULL)
 
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                                goto Fail;
 
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                }
 
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        }
 
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        Py_DECREF(args);
 
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        if (result == NULL)
 
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                PyErr_SetString(PyExc_TypeError,
 
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                           "reduce() of empty sequence with no initial value");
 
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        Py_DECREF(it);
 
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        return result;
 
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Fail:
 
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        Py_XDECREF(args);
 
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        Py_XDECREF(result);
 
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        Py_DECREF(it);
 
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        return NULL;
 
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}
 
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PyDoc_STRVAR(reduce_doc,
 
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"reduce(function, sequence[, initial]) -> value\n\
 
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\n\
 
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Apply a function of two arguments cumulatively to the items of a sequence,\n\
 
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from left to right, so as to reduce the sequence to a single value.\n\
 
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For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates\n\
 
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((((1+2)+3)+4)+5).  If initial is present, it is placed before the items\n\
 
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of the sequence in the calculation, and serves as a default when the\n\
 
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sequence is empty.");
 
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/* partial object **********************************************************/
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typedef struct {
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"Tools that operate on functions.");
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static PyMethodDef module_methods[] = {
 
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        {"reduce",      functools_reduce,     METH_VARARGS, reduce_doc},
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        {NULL,          NULL}           /* sentinel */
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};
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