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gh-133895: provide C99 Annex G return values for cmath's functions - #134995
skirpichev wants to merge 18 commits into
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Now this information is available as the "value" attribute of the ValueError exception object: ```pycon >>> import cmath >>> try: ... cmath.log(complex(-0.0, 0)) ... except ValueError as exc: ... print(exc.value) ... (-inf+3.141592653589793j) ``` Also uses the AC magic for return value of the cmath.rect().
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CC @abhigyan631 as author of #133923 |
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Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
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I changed exception handling along the way, suggested by @serhiy-storchaka. I hope I did that right. If so, I can adjust the math's pr. Now we add value to OverflowError's too. This reveals two bugs (in sinh and cosh), fixed. |
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| exc_string = PyUnicode_FromString("math range error"); | ||
| } | ||
| if (!exc_string) { | ||
| Py_DECREF(value); |
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I'm not very fond of stealing a reference here. Maybe we can just return -1 and make the DECREF in the caller?
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Then we just have to put Py_DECREF(value) unconditionally after every set_cmath_error(value) call.
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I think it'll be a bit cleaner (I find following code that doesn't steal references much easier, even if it sometimes leads to more lines). But since you're mainly the one maintaining math/cmath, it's up to you though. I'd appreciate a small comment in the function though to know that 'value' is stolen.
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I think it'll be a bit cleaner
Maybe. Lets other reviewers decide. Meanwhile, I left a comment.
you're mainly the one maintaining math/cmath
No :-)
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Well, you're someone with many contributions in this module!
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Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
This is a split-off pythongh-134995. The C17 standard says (cis(y) is defined as cos(y) + i sin(y)): * ccosh(+∞ + i0) returns +∞ + i0. * ccosh(+∞ + iy) returns +∞ cis(y), for finite nonzero y. and * csinh(+∞ + i0) returns +∞ + i0. * csinh(+∞ + iy) returns +∞ cis(y), for positive finite y. So far values, computed for exceptions, aren't accessible from the pure-Python world, yet we are trying to be correct in other places. The Lib/test/mathdata/cmath_testcases.txt has data points with correct numbers (see cosh0032 and sinh0032). Also, use AC magic for the rect() value.
This is a split-off pythongh-134995. The C17 standard says (cis(y) is defined as cos(y) + i sin(y)): * ccosh(+∞ + i0) returns +∞ + i0. * ccosh(+∞ + iy) returns +∞ cis(y), for finite nonzero y. and * csinh(+∞ + i0) returns +∞ + i0. * csinh(+∞ + iy) returns +∞ cis(y), for positive finite y. So far values, computed for exceptions, aren't accessible from the pure-Python world, yet we are trying to be correct in other places. The Lib/test/mathdata/cmath_testcases.txt has data points with correct numbers (see cosh0032 and sinh0032). Also, use AC magic for the rect() value.
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The scope of this change is larger than just the math module. The decision cannot be made by the reviewers of this PR alone. I'm not sure this is PEP worthy, but at least it's worth discussing with a wider audience. |
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@serhiy-storchaka, are you proposing some prior discussion in the "Ideas" section of https://discuss.python.org/? |
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Yes, please. |
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Now this information is available as the "value" attribute of raised exception objects, for example:
Also uses the AC magic for return value of the cmath.rect().
📚 Documentation preview 📚: https://cpython-previews--134995.org.readthedocs.build/