Please take me off the list Thanks
On Mon, Sep 29, 2014 at 10:32 AM, <[email protected]> wrote: > Send users mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.racket-lang.org/users/listinfo > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of users digest..." > > > [Racket Users list: > http://lists.racket-lang.org/users ] > > > Today's Topics: > > 1. Re: canonical index of Racket courses? [was: Summer programs > learning Racket for a student] ([email protected]) > 2. Re: typed racket, filters, and polymorphism (Konrad Hinsen) > 3. Re: aws/glacier: credential scope (Greg Hendershott) > 4. rsound docs (C K Kashyap) > 5. Re: typed racket, filters, and polymorphism (Robby Findler) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 28 Sep 2014 23:36:05 -0400 > From: [email protected] > To: Sam Tobin-Hochstadt <[email protected]>, Matthias Felleisen > <[email protected]> > Cc: Racket Users <[email protected]> > Subject: Re: [racket] canonical index of Racket courses? [was: Summer > programs learning Racket for a student] > Message-ID: > <CANwREeXtCqExVYCchvg4pvqFWs06tb4b=jtmu5zpdwtsaam...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > On Wed, Sep 17, 2014 at 10:51 AM, Sam Tobin-Hochstadt <[email protected]> > wrote: > >> I've now created a wiki page for this, with some initial content: >> https://github.com/plt/racket/wiki/Courses-using-Racket >> > > And now it's up to 22 revisions! Thanks for creating, Sam, and to everyone > who added to it. > > On Tue, Sep 16, 2014 at 8:43 PM, Matthias Felleisen >> <[email protected]> wrote: >> > Do you imagine listing college courses such as Brown's 17, which uses >> > DrRacket and the teaching languages? Or do you want Coursera courses that >> > everyone can access? >> > > I think linking to any class that makes educational materials publicly > available is valuable, but they should be divided into one section for > classes that don't require being admitted into a larger institution to > participate in (e.g. Bootstrap World, Coursera, summer programs for teens, > etc.), and another section for those that do. > > >> > And yes, we should probably create a wiki like thing for such an effort >> or >> > perhaps something like packages.racket-lang.org. I'll bring it up as we >> meet >> > in St Louis. >> > > Thanks, Matthias, and hope you all had a great time in St Louis. Looks like > it was a wonderful conference. > > Can the wiki page above be directly linked off racket-lang.org, perhaps a > bit more prominently? I hadn't even noticed > https://github.com/plt/racket/wiki before; now I see the link to it kind of > buried under the Contributing column of the Community section. Perhaps it's > not easy to find for others too. > > Thanks again for following up on this. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.racket-lang.org/users/archive/attachments/20140928/ac267b87/attachment-0001.html> > > ------------------------------ > > Message: 2 > Date: Mon, 29 Sep 2014 10:44:56 +0200 > From: Konrad Hinsen <[email protected]> > To: racket users list <[email protected]> > Subject: Re: [racket] typed racket, filters, and polymorphism > Message-ID: > <[email protected]> > Content-Type: text/plain; charset=us-ascii > > Matthias Felleisen writes: > > > Your message points out where gradual typing badly fails. > > Not just gradual typing. I am not aware of any good unit > implementation in any type system, with the exception of F# and Frink > whose type systems were explicitly modified to add unit checking as a > special case. Dependent types should permit a good solution, but I > haven't seen it done yet. > > The reason you need dependent types is that the product of two > measures is another measure with a new unit, so you must be able to > construct new types (representing units) from values. For example, a > length divided by a time yields a speed. Once you can do that, scaling > a unit (e.g. from meters to kilometers) becomes a special case. > > > In this specific case, you have two aspects of dimensionality: > > dimension per se (I am sure there is a word for it) and the chosen > > unit to represent it. > > The two terms used for this distinction are in fact "dimension" and > "unit". > > > If someone writes (area-of-rectangle 1 [mm] 1 [km]), there is > > nothing wrong with it -- except that the type checker should insert > > a coercion from mm to m and from km to m (multiplying/dividing by > > 1,000). > > That's a topic of hot debate in the scientific computing community. > Some argue that the type checker should consider your example as an > error, and not do any implicit conversion. The motivation is that the > expression you used is more likely to be a mistake than the meaningful > use of expressive language, since best practices recommend to use a > minimal set of units inside any piece of code. > > Anyway, that's a minor detail. If your type system can handle > automatic conversion, then it can also handle its absence. > > > Alexander D. Knauth writes: > > > What I had in mind was for the structs to be available at run-time, > > but that ideally the optimizer could take them out for the > > intermediate operations and put them back for the final result. > > You are actually adding a very Racket-specific requirement to the > already difficult units-as-types problem: the interplay between a > typed and an untyped dialect of the same language. I agree this would > be nice to have. > > Konrad. > > > ------------------------------ > > Message: 3 > Date: Mon, 29 Sep 2014 09:13:11 -0400 > From: Greg Hendershott <[email protected]> > To: Norman Gray <[email protected]> > Cc: [email protected] > Subject: Re: [racket] aws/glacier: credential scope > Message-ID: > <CAGspUn1Q5MvFq4i6q3KuoxBcszOpTh-RdjL=qwy+jbwhuur...@mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > It looks like the package server did eventually refresh a few hours ago: > > Last Updated: 9/28/2014, 4:21:56 PM ;change on GitHub > Last Checked: 9/29/2014, 7:51:37 AM ;pkgs.r-l.org refresh > > (I believe those times are US MT, -0600.) > > On Sun, Sep 28, 2014 at 6:10 PM, Greg Hendershott > <[email protected]> wrote: >> If you're in a hurry you could remove and re-install directly from GitHub: >> >> $ raco pkg remove aws >> $ raco pkg install git://github.com/greghendershott/aws >> >> On Sun, Sep 28, 2014 at 5:40 PM, Norman Gray <[email protected]> wrote: >>> >>> On 2014 Sep 28, at 22:17, Greg Hendershott <[email protected]> >>> wrote: >>> >>>>>> I clicked "update" on pkgs.racket-lang.org. But it seems to be slower >>>>>> than usual to refresh. After it does, you can `raco pkg update aws` to >>>>>> get the fix. >>>>> >>>>> Something seems wrong/stuck on pkgs.racket-lang.org. The top of the page >>>>> says: >>>>> >>>>> "update upload in progress: there may be inconsistencies below" >>>>> >>>>> It's been saying that for nearly an hour. >>>> >>>> Sometimes instead it says: >>>> >>>> "update upload being computed: the information below may not >>>> represent all recent changes and updates" >>>> >>>> It has switched between those two messages at various intervals over >>>> the last hour. >>> >>> And in case it's a useful data point, I'm getting >>> >>> % raco pkg update aws >>> Resolving "aws" via http://download.racket-lang.org/releases/6.1/catalog/ >>> Resolving "aws" via http://pkgs.racket-lang.org >>> No updates available >>> % >>> >>> And Greg, your fix is close enough to what I guessed might be the problem >>> that I'm now kicking myself for not just diving in and trying a fix myself. >>> Garhhhh... >>> >>> Norman >>> >>> >>> -- >>> Norman Gray : http://nxg.me.uk >>> SUPA School of Physics and Astronomy, University of Glasgow, UK >>> > > > ------------------------------ > > Message: 4 > Date: Mon, 29 Sep 2014 19:09:17 +0530 > From: C K Kashyap <[email protected]> > To: [email protected] > Subject: [racket] rsound docs > Message-ID: > <CAGdT1gq=e_-o9jcnamnoeqkek51vwxdpsfhhnsudzrojcwh...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi, > > I saw this nice racketcon video ( > https://www.youtube.com/watch?v=DkIVzHNjNEA&list=PLXr4KViVC0qI9t3lizitiFJ1cFIeN2Gdh&index=9) > on rsound. I've installed the rsound package and have been able to run the > example from the video. > > Is there a place that has mode documentation/tutorial on rsound? > > Regards, > Kashyap > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.racket-lang.org/users/archive/attachments/20140929/7ce26b08/attachment-0001.html> > > ------------------------------ > > Message: 5 > Date: Mon, 29 Sep 2014 09:32:40 -0500 > From: Robby Findler <[email protected]> > To: Konrad Hinsen <[email protected]> > Cc: racket users list <[email protected]> > Subject: Re: [racket] typed racket, filters, and polymorphism > Message-ID: > <CAL3TdONRKwUJ0pV3WhXDQvRgMT6mhSp6D6QGr4=w4y7g7ds...@mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > Just in case, here is one piece of related work from the PL world and > is probably a reasonable starting point for finding others' attempts > at this problem: > > http://research.microsoft.com/en-us/um/people/akenn/units/ > > Robby > > > On Mon, Sep 29, 2014 at 3:44 AM, Konrad Hinsen > <[email protected]> wrote: >> Matthias Felleisen writes: >> >> > Your message points out where gradual typing badly fails. >> >> Not just gradual typing. I am not aware of any good unit >> implementation in any type system, with the exception of F# and Frink >> whose type systems were explicitly modified to add unit checking as a >> special case. Dependent types should permit a good solution, but I >> haven't seen it done yet. >> >> The reason you need dependent types is that the product of two >> measures is another measure with a new unit, so you must be able to >> construct new types (representing units) from values. For example, a >> length divided by a time yields a speed. Once you can do that, scaling >> a unit (e.g. from meters to kilometers) becomes a special case. >> >> > In this specific case, you have two aspects of dimensionality: >> > dimension per se (I am sure there is a word for it) and the chosen >> > unit to represent it. >> >> The two terms used for this distinction are in fact "dimension" and >> "unit". >> >> > If someone writes (area-of-rectangle 1 [mm] 1 [km]), there is >> > nothing wrong with it -- except that the type checker should insert >> > a coercion from mm to m and from km to m (multiplying/dividing by >> > 1,000). >> >> That's a topic of hot debate in the scientific computing community. >> Some argue that the type checker should consider your example as an >> error, and not do any implicit conversion. The motivation is that the >> expression you used is more likely to be a mistake than the meaningful >> use of expressive language, since best practices recommend to use a >> minimal set of units inside any piece of code. >> >> Anyway, that's a minor detail. If your type system can handle >> automatic conversion, then it can also handle its absence. >> >> >> Alexander D. Knauth writes: >> >> > What I had in mind was for the structs to be available at run-time, >> > but that ideally the optimizer could take them out for the >> > intermediate operations and put them back for the final result. >> >> You are actually adding a very Racket-specific requirement to the >> already difficult units-as-types problem: the interplay between a >> typed and an untyped dialect of the same language. I agree this would >> be nice to have. >> >> Konrad. >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > > End of users Digest, Vol 109, Issue 75 > ************************************** ____________________ Racket Users list: http://lists.racket-lang.org/users
