Thank you Matthew. The new docs are crystal clear on what I want. Thank you.
Jay
On Mon, Apr 25, 2016 at 10:50 AM, Matthew Flatt <mfl...@cs.utah.edu> wrote:
> I agree that the spec for printing inexacts needs to be clarified.
>
> The current output format for flonums is consistent with scanf(), at
> least for non-infinity and non-NaN values, since it's produced by
> sprintf("%g", ...). Using "%g" means that the number sometimes prints
> with an "e..." part and sometimes not, though.
>
> For single- or extended-precision numbers, the output always includes
> an "f" or "t", and converting that character to "e" makes it compatible
> with scanf().
>
> At Mon, 25 Apr 2016 08:37:32 -0400, Jay McCarthy wrote:
>> Interesting. FWIW, my particular interest is something that I can
>> reliably send to other tools like Unix's bc or C's scanf. Going down
>> this line, however, did make me question using `number->string` all
>> over the place in demo Web programs.
>>
>> On Fri, Apr 22, 2016 at 10:22 AM, Robby Findler
>> <ro...@eecs.northwestern.edu> wrote:
>> > I think number->string is intended to be like `write` (ie written to
>> > be read back in hopefully without losing anything) and maybe you want
>> > something that's more in the spirit of `display`? (I.e., show
>> > something to a human in a hopefully useful format (at least that's how
>> > I see the difference between write and display)).
>> >
>> > There is a very very old attempt at this that was designed for use
>> > with DrRacket:
>> >
>> >
>> http://docs.racket-lang.org/framework/Number_Snip.html?q=number-snp#%28def._%28
>> %28lib._framework%2Fmain..rkt%29._number-snip~3amake-repeating-decimal-snip%29%
>> 29
>> >
>> > It does things like trying to make nice-looking fractions and show
>> > helpful amounts of decimals and deals with the fact that smallish
>> > rationals might turn into very very long decimals. It also requires a
>> > GUI context, so that might not be helpful.
>> >
>> > That said, I'm sure it could stand to be generalized and modernized
>> > and improved. It is used in DrRacket currently, so you can just write
>> > programs that produce numbers to play around with it.
>> >
>> > Robby
>> >
>> > On Fri, Apr 22, 2016 at 9:07 AM, Jay McCarthy <jay.mccar...@gmail.com>
>> > wrote:
>> >> This is complicated by single-flonums which seem to pretty out in the
>> >> reading format:
>> >>
>> >> (number->string 3f0) ===> "3.0f0"
>> >>
>> >> which is likely to look like an error to users.
>> >>
>> >> This makes me feel like I should never use number->string to show
>> >> something to a user... which seems strange.
>> >>
>> >> On Wed, Apr 20, 2016 at 1:28 PM, Jay McCarthy <jay.mccar...@gmail.com>
>> wrote:
>> >>> The documentation for (number->string z radix) is a bit sparse:
>> >>> "Returns a string that is the printed form of z in the base specified
>> >>> by radix. If z is inexact, radix must be 10, otherwise the
>> >>> exn:fail:contract exception is raised."
>> >>>
>> >>> In the case that z is inexact, are we guaranteed that it will always
>> >>> print as "<Sign>?<Digit>+<Dot><Digit>+" and never use... (a) the
>> >>> #i<Digit>+ format, (b) scientific notation, (c) not have a leading 0,
>> >>> and so on?
>> >>>
>> >>> Essentially, I would like to know that (number->string z 10) on an
>> >>> inexact is equivalent to (real->decimal-string z +inf.0) (if infinity
>> >>> were a legal value for the length of the decimal.)
>> >>>
>> >>> If not, there doesn't seem to be another function that reliably prints
>> >>> out floats.
>> >>>
>> >>> Jay
>> >>>
>> >>> --
>> >>> Jay McCarthy
>> >>> Associate Professor
>> >>> PLT @ CS @ UMass Lowell
>> >>> http://jeapostrophe.github.io
>> >>>
>> >>> "Wherefore, be not weary in well-doing,
>> >>> for ye are laying the foundation of a great work.
>> >>> And out of small things proceedeth that which is great."
>> >>> - D&C 64:33
>> >>
>> >>
>> >>
>> >> --
>> >> Jay McCarthy
>> >> Associate Professor
>> >> PLT @ CS @ UMass Lowell
>> >> http://jeapostrophe.github.io
>> >>
>> >> "Wherefore, be not weary in well-doing,
>> >> for ye are laying the foundation of a great work.
>> >> And out of small things proceedeth that which is great."
>> >> - D&C 64:33
>> >>
>> >> --
>> >> You received this message because you are subscribed to the Google Groups
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>> >> To unsubscribe from this group and stop receiving emails from it, send an
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>>
>>
>>
>> --
>> Jay McCarthy
>> Associate Professor
>> PLT @ CS @ UMass Lowell
>> http://jeapostrophe.github.io
>>
>> "Wherefore, be not weary in well-doing,
>> for ye are laying the foundation of a great work.
>> And out of small things proceedeth that which is great."
>> - D&C 64:33
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "Racket Users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
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--
Jay McCarthy
Associate Professor
PLT @ CS @ UMass Lowell
http://jeapostrophe.github.io
"Wherefore, be not weary in well-doing,
for ye are laying the foundation of a great work.
And out of small things proceedeth that which is great."
- D&C 64:33
--
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