New submission from Mark Dickinson: See thread starting at http://mail.python.org/pipermail/python-dev/2012-October/122241.html
The cmath module functions don't accept custom types that define __complex__, but whose __complex__ method returns a float rather than a complex number: Python 3.4.0a0 (default:53a7c2226a2b+, Oct 19 2012, 12:16:36) [GCC 4.2.1 (Apple Inc. build 5664)] on darwin Type "help", "copyright", "credits" or "license" for more information. >>> class A: ... def __complex__(self): return 42.0 ... >>> import cmath >>> cmath.sqrt(A()) Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: __complex__ should return a complex object In contrast, the complex constructor is happy to accept such objects. The root cause is that PyArg_ParseTuple's 'D' format calls PyComplex_AsCComplex (in Objects/complexobject.c), which refuses to accept a __complex__ result of type float. ---------- assignee: mark.dickinson components: Interpreter Core messages: 173379 nosy: mark.dickinson priority: normal severity: normal stage: needs patch status: open title: PyComplex_AsCComplex should allow __complex__ to return float. type: enhancement versions: Python 3.4 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue16290> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
