Author: antoine.pitrou Date: Sat Nov 27 23:00:11 2010 New Revision: 86842 Log: Issue #10518: Bring back the callable() builtin. Approved by Guido (BDFL) and Georg (RM). Modified: python/branches/py3k/Doc/library/functions.rst python/branches/py3k/Lib/test/test_bool.py python/branches/py3k/Lib/test/test_builtin.py python/branches/py3k/Misc/NEWS python/branches/py3k/Python/bltinmodule.c Modified: python/branches/py3k/Doc/library/functions.rst ============================================================================== --- python/branches/py3k/Doc/library/functions.rst (original) +++ python/branches/py3k/Doc/library/functions.rst Sat Nov 27 23:00:11 2010 @@ -121,6 +121,19 @@ Bytes objects can also be created with literals, see :ref:`strings`. +.. function:: callable(object) + + Return :const:`True` if the *object* argument appears callable, + :const:`False` if not. If this returns true, it is still possible that a + call fails, but if it is false, calling *object* will never succeed. + Note that classes are callable (calling a class returns a new instance); + instances are callable if their class has a :meth:`__call__` method. + + .. versionadded:: 3.2 + This function was first removed in Python 3.0 and then brought back + in Python 3.2. + + .. function:: chr(i) Return the string representing a character whose Unicode codepoint is the integer Modified: python/branches/py3k/Lib/test/test_bool.py ============================================================================== --- python/branches/py3k/Lib/test/test_bool.py (original) +++ python/branches/py3k/Lib/test/test_bool.py Sat Nov 27 23:00:11 2010 @@ -174,8 +174,8 @@ self.assertIs(hasattr([], "wobble"), False) def test_callable(self): - self.assertIs(hasattr(len, '__call__'), True) - self.assertIs(hasattr(1, '__call__'), False) + self.assertIs(callable(len), True) + self.assertIs(callable(1), False) def test_isinstance(self): self.assertIs(isinstance(True, bool), True) Modified: python/branches/py3k/Lib/test/test_builtin.py ============================================================================== --- python/branches/py3k/Lib/test/test_builtin.py (original) +++ python/branches/py3k/Lib/test/test_builtin.py Sat Nov 27 23:00:11 2010 @@ -207,22 +207,39 @@ self.assertTrue(isinstance(x, int)) self.assertEqual(-x, sys.maxsize+1) - # XXX(nnorwitz): This test case for callable should probably be removed. def test_callable(self): - self.assertTrue(hasattr(len, '__call__')) + self.assertTrue(callable(len)) + self.assertFalse(callable("a")) + self.assertTrue(callable(callable)) + self.assertTrue(callable(lambda x, y: x + y)) + self.assertFalse(callable(__builtins__)) def f(): pass - self.assertTrue(hasattr(f, '__call__')) - class C: + self.assertTrue(callable(f)) + + class C1: def meth(self): pass - self.assertTrue(hasattr(C, '__call__')) - x = C() - self.assertTrue(hasattr(x.meth, '__call__')) - self.assertTrue(not hasattr(x, '__call__')) - class D(C): + self.assertTrue(callable(C1)) + c = C1() + self.assertTrue(callable(c.meth)) + self.assertFalse(callable(c)) + + # __call__ is looked up on the class, not the instance + c.__call__ = None + self.assertFalse(callable(c)) + c.__call__ = lambda self: 0 + self.assertFalse(callable(c)) + del c.__call__ + self.assertFalse(callable(c)) + + class C2(object): def __call__(self): pass - y = D() - self.assertTrue(hasattr(y, '__call__')) - y() + c2 = C2() + self.assertTrue(callable(c2)) + c2.__call__ = None + self.assertTrue(callable(c2)) + class C3(C2): pass + c3 = C3() + self.assertTrue(callable(c3)) def test_chr(self): self.assertEqual(chr(32), ' ') Modified: python/branches/py3k/Misc/NEWS ============================================================================== --- python/branches/py3k/Misc/NEWS (original) +++ python/branches/py3k/Misc/NEWS Sat Nov 27 23:00:11 2010 @@ -10,6 +10,8 @@ Core and Builtins ----------------- +- Issue #10518: Bring back the callable() builtin. + - Issue #8879. Add os.link support for Windows. - Issue #10027. st_nlink was not being set on Windows calls to os.stat or Modified: python/branches/py3k/Python/bltinmodule.c ============================================================================== --- python/branches/py3k/Python/bltinmodule.c (original) +++ python/branches/py3k/Python/bltinmodule.c Sat Nov 27 23:00:11 2010 @@ -311,6 +311,20 @@ Return the binary representation of an integer or long integer."); +static PyObject * +builtin_callable(PyObject *self, PyObject *v) +{ + return PyBool_FromLong((long)PyCallable_Check(v)); +} + +PyDoc_STRVAR(callable_doc, +"callable(object) -> bool\n\ +\n\ +Return whether the object is callable (i.e., some kind of function).\n\ +Note that classes are callable, as are instances of classes with a\n\ +__call__() method."); + + typedef struct { PyObject_HEAD PyObject *func; @@ -2242,6 +2256,7 @@ {"any", builtin_any, METH_O, any_doc}, {"ascii", builtin_ascii, METH_O, ascii_doc}, {"bin", builtin_bin, METH_O, bin_doc}, + {"callable", builtin_callable, METH_O, callable_doc}, {"chr", builtin_chr, METH_VARARGS, chr_doc}, {"compile", (PyCFunction)builtin_compile, METH_VARARGS | METH_KEYWORDS, compile_doc}, {"delattr", builtin_delattr, METH_VARARGS, delattr_doc},