[issue40801] Expose PyFloat_AsDouble at Python level: operator.as_float?

[Serhiy Storchaka]

Serhiy Storchaka <storchaka+cpython at gmail.com> added the comment:

The problem with the roundtrip PyFloat_FromDouble(PyFloat_AsDouble(obj)) is that (in contrary to PyNumber_Index()) it is lossy. Converting Decimal, Fraction, float128 to float before using it in expression can lead to loss of precision.

So such conversion looks to me less useful than operator.index().

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<https://bugs.python.org/issue40801>
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