Sorry for the double-post -- I already asked this in d-learn, but this may be a better place to ask.

What's the current state of affairs and roadmap for inclusion of rational number support in D?  I've come across David Simcha's work:
http://cis.jhu.edu/~dsimcha/d/phobos/std_rational.html

... and a feature request on the bugzilla:
http://d.puremagic.com/issues/show_bug.cgi?id=7885

... but this isn't mentioned at all in the review queue:
http://prowiki.org/wiki4d/wiki.cgi?ReviewQueue

What's the status of work/planning for this feature and is there any kind of ETA for when it might land in Phobos?

Thanks and best wishes,

    -- Joe

On Thursday, 7 June 2012 at 17:49:22 UTC, Joseph Rushton Wakeling wrote:
> Sorry for the double-post -- I already asked this in d-learn, but this may be a better place to ask.
>
> What's the current state of affairs and roadmap for inclusion of rational number support in D?  I've come across David Simcha's work:
> http://cis.jhu.edu/~dsimcha/d/phobos/std_rational.html
>
> ... and a feature request on the bugzilla:
> http://d.puremagic.com/issues/show_bug.cgi?id=7885
>
> ... but this isn't mentioned at all in the review queue:
> http://prowiki.org/wiki4d/wiki.cgi?ReviewQueue
>
> What's the status of work/planning for this feature and is there any kind of ETA for when it might land in Phobos?
>
> Thanks and best wishes,
>
>     -- Joe

I don't think anyone intends to ignore your posts, it's just that we don't have the answer. Jonathan Davis has a new thread regarding the review queue. You might get answers there.

I think there is a tendency for discussions in this group to focus on language internals and features rather than useful but mundane things. As a last resort you could probably check and/or complete the rational number code and put it in the review queue yourself. Most code here is licensed to allow that.

Taking a little longer view, we definitely need a better process for inclusion of new modules into phobos. Maybe, as you suggest, a roadmap for proposed modules, with dates for implementation and reviews.

Paul

On 08/06/12 18:06, Paul D. Anderson wrote:
> I don't think anyone intends to ignore your posts, it's just that we don't have
> the answer. Jonathan Davis has a new thread regarding the review queue. You
> might get answers there.

It wasn't really that I was feeling ignored (OK, put this as a tribute to the speed at which questions are usually answered:-), more that I thought the discussion might be more useful/suited here as it's about a module under development.  Again, sorry for the double post.

> I think there is a tendency for discussions in this group to focus on language
> internals and features rather than useful but mundane things. As a last resort
> you could probably check and/or complete the rational number code and put it in
> the review queue yourself. Most code here is licensed to allow that.

I'll take a look and see what I can do.

> Taking a little longer view, we definitely need a better process for inclusion
> of new modules into phobos. Maybe, as you suggest, a roadmap for proposed
> modules, with dates for implementation and reviews.

I guess it's tricky because there are only a limited number of people who can review the code, so it must be difficult to set definite time targets.  But it could be nice to have e.g. a priority wish list so that we can see what kinds of contributions would be most useful/welcome.

On 07/06/2012 18:49, Joseph Rushton Wakeling wrote:
> Sorry for the double-post -- I already asked this in d-learn, but this may be a better
> place to ask.
>
> What's the current state of affairs and roadmap for inclusion of rational number support
> in D?

Including it in D seems very unlikely.

Including it in Phobos, OTOH, is another matter.

> I've come across David Simcha's work:
> http://cis.jhu.edu/~dsimcha/d/phobos/std_rational.html
>
> ... and a feature request on the bugzilla:
> http://d.puremagic.com/issues/show_bug.cgi?id=7885
<snip>

Well, do these work at the moment?

If so, I suggest you use one of them for now.  If you're mainly just doing simple arithmetic with them, it probably wouldn't be too much work to convert your code to use the Phobos rational type when/if it gets one.

Stewart.

On Saturday, 9 June 2012 at 01:11:49 UTC, Stewart Gordon wrote:
> On 07/06/2012 18:49, Joseph Rushton Wakeling wrote:
>> Sorry for the double-post -- I already asked this in d-learn, but this may be a better
>> place to ask.
>>
>> What's the current state of affairs and roadmap for inclusion of rational number support
>> in D?
>
> Including it in D seems very unlikely.
>
> Including it in Phobos, OTOH, is another matter.
>
>> I've come across David Simcha's work:
>> http://cis.jhu.edu/~dsimcha/d/phobos/std_rational.html
>>
>> ... and a feature request on the bugzilla:
>> http://d.puremagic.com/issues/show_bug.cgi?id=7885
> <snip>
>
> Well, do these work at the moment?
>
> If so, I suggest you use one of them for now.  If you're mainly just doing simple arithmetic with them, it probably wouldn't be too much work to convert your code to use the Phobos rational type when/if it gets one.
>
> Stewart.

I've never had any use for rational numbers as have 99% of developers I believe. Maybe I'm overlooking something, but I see only two possible usages of them: math packages and length quotations in the english system. Because of this, I'd rather see them in Deimos than in Phobos.

SomeDude:

> I've never had any use for rational numbers as have 99% of developers I believe. Maybe I'm overlooking something, but I see only two possible usages of them: math packages and length quotations in the english system. Because of this, I'd rather see them in Deimos than in Phobos.

I have had to use Rational nunbers in D two or three times (once during simplification of expressions that contain operations among integer numbers, to not lose exact precision with floating point numbers). I have written a rationals module for D1 and later I have converted it to D2. So you see two persons that have implemented them.

It's a small module, that uses std.bigint, it's not a binding to C code, so putting it in Deimos is not necessary. I'd like a rationals module in Phobos.

Bye,
bearophile

On Saturday, 9 June 2012 at 01:11:49 UTC, Stewart Gordon wrote:
> Including it in D seems very unlikely.
>
> Including it in Phobos, OTOH, is another matter.

My bad phrasing.  Of course in Phobos.


On 09/06/12 08:25, SomeDude wrote:
> I've never had any use for rational numbers as have 99% of developers I believe.
> Maybe I'm overlooking something, but I see only two possible usages of them:
> math packages and length quotations in the english system. Because of this, I'd
> rather see them in Deimos than in Phobos.

In fact the application I had in mind was for music software, where you want to be able to store pitch changes in fractions of a whole tone.  In that context it's important that adding up those changes be guaranteed to produce exact results.

e.g. if you take middle C and raise it by 1 whole tone _exactly_ you arrive at the note D.  If you raise it by 0.99999999999999999999999999995 instead, how does your software reliably handle this?

On 09.06.2012 21:47, Joseph Rushton Wakeling wrote:
> On Saturday, 9 June 2012 at 01:11:49 UTC, Stewart Gordon wrote:
>> Including it in D seems very unlikely.
>>
>> Including it in Phobos, OTOH, is another matter.
>
> My bad phrasing. Of course in Phobos.
>
>
> On 09/06/12 08:25, SomeDude wrote:
>> I've never had any use for rational numbers as have 99% of developers
>> I believe.
>> Maybe I'm overlooking something, but I see only two possible usages of
>> them:
>> math packages and length quotations in the english system. Because of
>> this, I'd
>> rather see them in Deimos than in Phobos.
>
> In fact the application I had in mind was for music software, where you
> want to be able to store pitch changes in fractions of a whole tone. In
> that context it's important that adding up those changes be guaranteed
> to produce exact results.
>
> e.g. if you take middle C and raise it by 1 whole tone _exactly_ you
> arrive at the note D. If you raise it by 0.99999999999999999999999999995
> instead, how does your software reliably handle this?

Prescaling works just fine. That is use plain integer and assume it holds value in the smallest fraction possible. Then define functions that do scale and round it to tone, note etc.

-- 
Dmitry Olshansky

On 09/06/12 16:08, bearophile wrote:
> I have had to use Rational nunbers in D two or three times (once during
> simplification of expressions that contain operations among integer numbers, to
> not lose exact precision with floating point numbers). I have written a
> rationals module for D1 and later I have converted it to D2. So you see two
> persons that have implemented them.
>
> It's a small module, that uses std.bigint, it's not a binding to C code, so
> putting it in Deimos is not necessary. I'd like a rationals module in Phobos.

... so, I can lend my voice to support inclusion of your module :-)  Is there anything more practical that I could do to assist?

On 09/06/2012 18:47, Joseph Rushton Wakeling wrote:
> On Saturday, 9 June 2012 at 01:11:49 UTC, Stewart Gordon wrote:
>> Including it in D seems very unlikely.
>>
>> Including it in Phobos, OTOH, is another matter.
>
> My bad phrasing.  Of course in Phobos.
>
>
> On 09/06/12 08:25, SomeDude wrote:
>> I've never had any use for rational numbers as have 99% of developers I believe.
>> Maybe I'm overlooking something, but I see only two possible usages of them:
>> math packages and length quotations in the english system. Because of this, I'd
>> rather see them in Deimos than in Phobos.
>
> In fact the application I had in mind was for music software, where you want to be able to
> store pitch changes in fractions of a whole tone.  In that context it's important that
> adding up those changes be guaranteed to produce exact results.
>
> e.g. if you take middle C and raise it by 1 whole tone _exactly_ you arrive at the note
> D.  If you raise it by 0.99999999999999999999999999995 instead, how does your software
> reliably handle this?

By using an integer type to store pitches in such a way that the semitone is the basic unit.

Do you compose music that makes use of demisemitones, thirds of tones, and so on?

Stewart.