I probably should have added "user exposed" or something to my comment. Those extra bits certainly seem to offer compiler optimization possibilities, as apparently SpiderMonkey does with WASM.
I can easily *imagine* a library like NumPy or PyTorch deciding to expose something useful with those 52 unused mantissa bits. But that's some future version, if ever. On Sat, Sep 12, 2020, 2:16 PM Cade Brown <brown.c...@gmail.com> wrote: > As per tagged nans, check for JavaScript tagged NaN optimization. > Essentially, the tag of the NaN (i.e. the mantissa) is interpreted as a > pointer. Obviously, this is a very advanced use case, probably not worth > Python guaranteeing such behavior. > Here is one article: > https://brionv.com/log/2018/05/17/javascript-engine-internals-nan-boxing/ > > On Sat, Sep 12, 2020, 8:10 PM David Mertz <me...@gnosis.cx> wrote: > >> On Sat, Sep 12, 2020, 2:02 PM Steven D'Aprano <st...@pearwood.info> >> wrote: >> >>> In general though, Python doesn't support generating the full range of >>> NANs with payloads directly. >> >> >> I've researched this a little bit for discussion in a book I'm writing, >> and I have not been able to identify ANY widely used programming language >> or tool that does anything meaningful with the NaN payloads. >> >> It's possible I've missed something, but certainly not the top 20 >> languages are libraries that might come to mind. >> _______________________________________________ >> Python-ideas mailing list -- python-ideas@python.org >> To unsubscribe send an email to python-ideas-le...@python.org >> https://mail.python.org/mailman3/lists/python-ideas.python.org/ >> Message archived at >> https://mail.python.org/archives/list/python-ideas@python.org/message/FZ7QGRV5IRV2WFX6YFDO7KR5C2Y5BJHG/ >> Code of Conduct: http://python.org/psf/codeofconduct/ >> >
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