diff options
| -rw-r--r-- | Lib/test/test_iter.py | 44 | ||||
| -rw-r--r-- | Misc/NEWS | 17 | ||||
| -rw-r--r-- | Python/bltinmodule.c | 94 |
3 files changed, 107 insertions, 48 deletions
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py index 5b9bf65..952ab66 100644 --- a/Lib/test/test_iter.py +++ b/Lib/test/test_iter.py @@ -275,4 +275,48 @@ class TestCase(unittest.TestCase): except OSError: pass + # Test filter()'s use of iterators. + def test_builtin_filter(self): + self.assertEqual(filter(None, SequenceClass(5)), range(1, 5)) + self.assertEqual(filter(None, SequenceClass(0)), []) + self.assertEqual(filter(None, ()), ()) + self.assertEqual(filter(None, "abc"), "abc") + + d = {"one": 1, "two": 2, "three": 3} + self.assertEqual(filter(None, d), d.keys()) + + self.assertRaises(TypeError, filter, None, list) + self.assertRaises(TypeError, filter, None, 42) + + class Boolean: + def __init__(self, truth): + self.truth = truth + def __nonzero__(self): + return self.truth + True = Boolean(1) + False = Boolean(0) + + class Seq: + def __init__(self, *args): + self.vals = args + def __iter__(self): + class SeqIter: + def __init__(self, vals): + self.vals = vals + self.i = 0 + def __iter__(self): + return self + def next(self): + i = self.i + self.i = i + 1 + if i < len(self.vals): + return self.vals[i] + else: + raise StopIteration + return SeqIter(self.vals) + + seq = Seq(*([True, False] * 25)) + self.assertEqual(filter(lambda x: not x, seq), [False]*25) + self.assertEqual(filter(lambda x: not x, iter(seq)), [False]*25) + run_unittest(TestCase) @@ -17,7 +17,8 @@ Core - The following functions were generalized to work nicely with iterator arguments: - list() + filter() + list() What's New in Python 2.1 (final)? @@ -236,7 +237,7 @@ Tools - IDLE: syntax warnings in interactive mode are changed into errors. - Some improvements to Tools/webchecker (ignore some more URL types, - follow some more links). + follow some more links). - Brought the Tools/compiler package up to date. @@ -324,23 +325,23 @@ Python/C API in Flags and take an extra argument, a PyCompilerFlags *; examples: PyRun_AnyFileExFlags(), PyRun_InteractiveLoopFlags(). These variants may be removed in Python 2.2, when nested scopes are - mandatory. + mandatory. Distutils - the sdist command now writes a PKG-INFO file, as described in PEP 241, into the release tree. -- several enhancements to the bdist_wininst command from Thomas Heller +- several enhancements to the bdist_wininst command from Thomas Heller (an uninstaller, more customization of the installer's display) - from Jack Jansen: added Mac-specific code to generate a dialog for users to specify the command-line (because providing a command-line with - MacPython is awkward). Jack also made various fixes for the Mac + MacPython is awkward). Jack also made various fixes for the Mac and the Metrowerks compiler. - -- added 'platforms' and 'keywords' to the set of metadata that can be - specified for a distribution. + +- added 'platforms' and 'keywords' to the set of metadata that can be + specified for a distribution. - applied patches from Jason Tishler to make the compiler class work with Cygwin. diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c index 8572cc8..1051374 100644 --- a/Python/bltinmodule.c +++ b/Python/bltinmodule.c @@ -162,53 +162,65 @@ Note that classes are callable, as are instances with a __call__() method."; static PyObject * builtin_filter(PyObject *self, PyObject *args) { - PyObject *func, *seq, *result; - PySequenceMethods *sqf; - int len; + PyObject *func, *seq, *result, *it; + int len; /* guess for result list size */ register int i, j; if (!PyArg_ParseTuple(args, "OO:filter", &func, &seq)) return NULL; - if (PyString_Check(seq)) { - PyObject *r = filterstring(func, seq); - return r; - } + /* Strings and tuples return a result of the same type. */ + if (PyString_Check(seq)) + return filterstring(func, seq); + if (PyTuple_Check(seq)) + return filtertuple(func, seq); - if (PyTuple_Check(seq)) { - PyObject *r = filtertuple(func, seq); - return r; - } + /* Get iterator. */ + it = PyObject_GetIter(seq); + if (it == NULL) + return NULL; - sqf = seq->ob_type->tp_as_sequence; - if (sqf == NULL || sqf->sq_length == NULL || sqf->sq_item == NULL) { - PyErr_SetString(PyExc_TypeError, - "filter() arg 2 must be a sequence"); - goto Fail_2; + /* Guess a result list size. */ + len = -1; /* unknown */ + if (PySequence_Check(seq) && + seq->ob_type->tp_as_sequence->sq_length) { + len = PySequence_Size(seq); + if (len < 0) + PyErr_Clear(); } + if (len < 0) + len = 8; /* arbitrary */ - if ((len = (*sqf->sq_length)(seq)) < 0) - goto Fail_2; - + /* Get a result list. */ if (PyList_Check(seq) && seq->ob_refcnt == 1) { + /* Eww - can modify the list in-place. */ Py_INCREF(seq); result = seq; } else { - if ((result = PyList_New(len)) == NULL) - goto Fail_2; + result = PyList_New(len); + if (result == NULL) + goto Fail_it; } + /* Build the result list. */ for (i = j = 0; ; ++i) { PyObject *item, *good; int ok; - if ((item = (*sqf->sq_item)(seq, i)) == NULL) { - if (PyErr_ExceptionMatches(PyExc_IndexError)) { - PyErr_Clear(); - break; + item = PyIter_Next(it); + if (item == NULL) { + /* We're out of here in any case, but if this is a + * StopIteration exception it's expected, but if + * any other kind of exception it's an error. + */ + if (PyErr_Occurred()) { + if (PyErr_ExceptionMatches(PyExc_StopIteration)) + PyErr_Clear(); + else + goto Fail_result_it; } - goto Fail_1; + break; } if (func == Py_None) { @@ -217,43 +229,45 @@ builtin_filter(PyObject *self, PyObject *args) } else { PyObject *arg = Py_BuildValue("(O)", item); - if (arg == NULL) - goto Fail_1; + if (arg == NULL) { + Py_DECREF(item); + goto Fail_result_it; + } good = PyEval_CallObject(func, arg); Py_DECREF(arg); if (good == NULL) { Py_DECREF(item); - goto Fail_1; + goto Fail_result_it; } } ok = PyObject_IsTrue(good); Py_DECREF(good); if (ok) { - if (j < len) { - if (PyList_SetItem(result, j++, item) < 0) - goto Fail_1; - } + if (j < len) + PyList_SET_ITEM(result, j, item); else { int status = PyList_Append(result, item); - j++; Py_DECREF(item); if (status < 0) - goto Fail_1; + goto Fail_result_it; } - } else { - Py_DECREF(item); + ++j; } + else + Py_DECREF(item); } + /* Cut back result list if len is too big. */ if (j < len && PyList_SetSlice(result, j, len, NULL) < 0) - goto Fail_1; + goto Fail_result_it; return result; -Fail_1: +Fail_result_it: Py_DECREF(result); -Fail_2: +Fail_it: + Py_DECREF(it); return NULL; } |