René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Make PyComplex_RealAsDouble/ImagAsDouble use __complex__","articleBody":"The C-API docs says: \"Return the real/imag part of op as a C double.\"  But the real code looks like:\r\n```c\r\nPyComplex_RealAsDouble(PyObject *op)\r\n{\r\n    if (PyComplex_Check(op)) {\r\n        return ((PyComplexObject *)op)-\u003ecval.real;\r\n    }\r\n    else {\r\n        return PyFloat_AsDouble(op);\r\n    }\r\n}\r\n```\r\nSo, we assume instead that the ``op`` is a float-like class (a subtype of or something with a ``__float__`` dunder method).  Instead, we should look on the ``__complex__`` method in the ``else`` branch.  This is an issue like #44670, I think.\r\n\r\nMinor issue: these functions aren't tested, only indirectly with ``format()`` (that will not trigger all possible cases).\r\n\r\nEdit:\r\nThe current ``PyComplex_ImagAsDouble()`` silently returns ``0.0`` for all non-PyComplexObject objects (or subtypes of).  I think it's a bug and we should return ``-1.0`` instead and set the error indicator.\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-109647\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/skirpichev","@type":"Person","name":"skirpichev"},"datePublished":"2023-09-20T06:07:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/109598/cpython/issues/109598"}