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Re: reading a float?
brucehoult@pobox.com (Bruce Hoult) writes:
> Decode and make them from *what*? The standard C library certainly has
> functions that parse a string and produce a float.
> Are you talking about putting together the binary representation of a
> float by using bit-twiddling instructions? Ick.
You are right. Using atof(3) is probably the best solution--I was
replying to Chris' suggestion talking about an implementation in Common
Lisp or Dylan, and I was thinking about _printing_ floats, too. When I
translated CMUCL's implementation of FORMAT to Dylan I couldn't figure
out how to do flexible floating-point printing portably (and that part
is still broken/missing), so my idea was that if ``bit-twiddling'' was
needed anyway (for printing) then reading floats could be done in Dylan
as well.
> It's hard to see how you can go past 1). Doing this properly is actually
> far harder than I've intimated above -- people actually write academic
> papers on the subject.
Given portable bit-twiddling-functions it's as easy as implementing the
algorithms presented in these papers.
> Someone's already done the hard work of getting
> fast, accurate FP conversions to work on any machine that has a C
> compiler. Why not use it?
I didn't find a way to use it for printing. Patches or hints are
welcome.
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