# Latest **URL:** https://racket.discourse.group/latest.md?page=55 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 56 --- ## [Where to report typos in the docs?](https://racket.discourse.group/t/where-to-report-typos-in-the-docs/1256)
**Author:** [@jgomo3](https://racket.discourse.group/u/jgomo3)\ **Replies:** 3\ **Last updated:** [August 27, 2022, 1:59pm UTC](https://racket.discourse.group/t/where-to-report-typos-in-the-docs/1256 "2022-08-27T13:59:17Z")
The documentation for gcd of the BSL language says Determines the greatest common divisor of two integers (exact or inexact). But it actually accepts many arguments. (The same happens in the lcm function). I was abo… --- ## [Purely Functional Data Structures anyone?](https://racket.discourse.group/t/purely-functional-data-structures-anyone/1246)
**Author:** [@dominik.pantucek](https://racket.discourse.group/u/dominik.pantucek)\ **Replies:** 10\ **Last updated:** [August 26, 2022, 8:30pm UTC](https://racket.discourse.group/t/purely-functional-data-structures-anyone/1246 "2022-08-26T20:30:17Z")
While working on my own non-TR implementation of PFDS RB Tree following\[1\] and heavily consulting the pfds implementation in the Racket package catalog\[2\]\[3\]\[4\], when trying to implement key deletion, I found an issue wi… --- ## [Tiling geographic regions](https://racket.discourse.group/t/tiling-geographic-regions/1255)
**Author:** [@alexh](https://racket.discourse.group/u/alexh)\ **Replies:** 2\ **Last updated:** [August 26, 2022, 12:46pm UTC](https://racket.discourse.group/t/tiling-geographic-regions/1255 "2022-08-26T12:46:47Z")
So, I updated my geoid package to support region tiling. This is the process of subdividing any region on the globe into a list of squares which are uniquely identified using 64 bit numbers -- this effectively change… --- ## [Running a selected set of check-expect settings](https://racket.discourse.group/t/running-a-selected-set-of-check-expect-settings/1252)
**Author:** [@jgomo3](https://racket.discourse.group/u/jgomo3)\ **Replies:** 3\ **Last updated:** [August 24, 2022, 10:17am UTC](https://racket.discourse.group/t/running-a-selected-set-of-check-expect-settings/1252 "2022-08-24T10:17:04Z")
How can I check only one single check-expect or a selection of those in DrRacket? All I know to do now is to run the whole file and review the reports from all check-expects, but having half-baked wish functions, it cou… --- ## [Unexpected behavior permutations vs in-permutations](https://racket.discourse.group/t/unexpected-behavior-permutations-vs-in-permutations/1253)
**Author:** [@simonls](https://racket.discourse.group/u/simonls)\ **Replies:** 2\ **Last updated:** [August 24, 2022, 1:28am UTC](https://racket.discourse.group/t/unexpected-behavior-permutations-vs-in-permutations/1253 "2022-08-24T01:28:05Z")
When I use permutations or in-permutations I get different orderings for the permutations returned, is there some good reason for that? From the documentation I would expect identical behaviour, it states: (in-permuta… --- ## [Can you save a jpeg image?](https://racket.discourse.group/t/can-you-save-a-jpeg-image/1192)
**Author:** [@KenMax](https://racket.discourse.group/u/KenMax)\ **Replies:** 4\ **Last updated:** [August 24, 2022, 1:11am UTC](https://racket.discourse.group/t/can-you-save-a-jpeg-image/1192 "2022-08-24T01:11:15Z")
I need to be able to rescale some jpeg images. The 2htdp/image library has bitmap and scale procedures, which is almost exactly what I need, except I have not found a way to save the image back as a jpeg, only as a png. … --- ## [\[BSL\] Would it be considered bad practice to name custom function with the same pattern as selectors?](https://racket.discourse.group/t/bsl-would-it-be-considered-bad-practice-to-name-custom-function-with-the-same-pattern-as-selectors/1251)
**Author:** [@jgomo3](https://racket.discourse.group/u/jgomo3)\ **Replies:** 1\ **Last updated:** [August 24, 2022, 12:08am UTC](https://racket.discourse.group/t/bsl-would-it-be-considered-bad-practice-to-name-custom-function-with-the-same-pattern-as-selectors/1251 "2022-08-24T00:08:02Z")
I'm reading How to Design Programs. This question is about the Beginning Student Language. Doing the exercise of the Graphical Editor, we define an structure like this: (define-struct editor \[pre post\]) Which implies… --- ## [Transforming the code to use recursion](https://racket.discourse.group/t/transforming-the-code-to-use-recursion/1236)
**Author:** [@erfan](https://racket.discourse.group/u/erfan)\ **Replies:** 21\ **Last updated:** [August 23, 2022, 12:07pm UTC](https://racket.discourse.group/t/transforming-the-code-to-use-recursion/1236 "2022-08-23T12:07:29Z")
Hi all! I have written a simple program that uses the imperative style to calculate prime numbers up to a given number. I understand however that imperative style (set!) should be avoided when possible and recursion is … --- ## [Pointful? : A mixin+interface for finding identified children](https://racket.discourse.group/t/pointful-a-mixin-interface-for-finding-identified-children/1247)
**Author:** [@dstorrs](https://racket.discourse.group/u/dstorrs)\ **Replies:** 7\ **Last updated:** [August 22, 2022, 10:51pm UTC](https://racket.discourse.group/t/pointful-a-mixin-interface-for-finding-identified-children/1247 "2022-08-22T22:51:44Z")
I'm running into a challenge with the GUI, I have a solution that I am considering putting into a module and posting on the package server. I'd like some feedback on whether this seems useful or if there's a better way… --- ## [Chez for architectures without native backends](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950)
**Author:** [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\ **Replies:** 29\ **Last updated:** [August 21, 2022, 9:04pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950 "2022-08-21T21:04:48Z")
In light of this enhancement in Racket 8.5: I'm trying to understand how to adapt Guix's package of Racket's Chez Scheme variant to support e.g. powerpc64le-unknown-linux-gnu, which is one of Guix's supported systems. … --- ## [How do I find the (dis|en)enabled status of a control?](https://racket.discourse.group/t/how-do-i-find-the-dis-en-enabled-status-of-a-control/1242)
**Author:** [@dstorrs](https://racket.discourse.group/u/dstorrs)\ **Replies:** 2\ **Last updated:** [August 20, 2022, 1:34am UTC](https://racket.discourse.group/t/how-do-i-find-the-dis-en-enabled-status-of-a-control/1242 "2022-08-20T01:34:29Z")
The Reference specifies how to set the enabled/disabled status of a window/control/etc, and there is also on-superwindow-enable, which provides a hook for handling state changes to a window's enabled/disabled status, but… --- ## [Number oddities](https://racket.discourse.group/t/number-oddities/1171)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 7\ **Last updated:** [August 19, 2022, 8:43pm UTC](https://racket.discourse.group/t/number-oddities/1171 "2022-08-19T20:43:50Z")
(No, the subject isn't about odd and even numbers. :wink: ) A part of this post is complaining :wink: and a part is asking for your experiences and advice. I'm currently reading the chapter on numbers in the Racket Ref… --- ## [Scribble: Pre rendered HTML](https://racket.discourse.group/t/scribble-pre-rendered-html/1216)
**Author:** [@soegaard](https://racket.discourse.group/u/soegaard)\ **Replies:** 5\ **Last updated:** [August 18, 2022, 7:51pm UTC](https://racket.discourse.group/t/scribble-pre-rendered-html/1216 "2022-08-18T19:51:51Z")
Hi All, I am working on pyffi a way to use Python libraries from Racket. As an example I want to use Pygments as a showcase. Pygments is a generic syntax highlighter and more than 500 languages are supported. It woul… --- ## [Rendering \`6/3\` in code example at prompt](https://racket.discourse.group/t/rendering-6-3-in-code-example-at-prompt/1238)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 3\ **Last updated:** [August 17, 2022, 7:23pm UTC](https://racket.discourse.group/t/rendering-6-3-in-code-example-at-prompt/1238 "2022-08-17T19:23:10Z")
With the help of scribble/example, I try to render this Scribble code: @examples\[ (integer? 6/3)\] This renders as \> (integer? 2) #t presumably because 6/3 is evaluated before rendering, maybe even before Scribble s… --- ## [What kind of spline does \`draw-spline\` draw?](https://racket.discourse.group/t/what-kind-of-spline-does-draw-spline-draw/1231)
**Author:** [@benknoble](https://racket.discourse.group/u/benknoble)\ **Replies:** 8\ **Last updated:** [August 16, 2022, 7:23pm UTC](https://racket.discourse.group/t/what-kind-of-spline-does-draw-spline-draw/1231 "2022-08-16T19:23:03Z")
Alternately: how can I convert points that I liked with draw-spline to points consistent with curve-to? I'm working on drawing some fire with racket/draw + pict (using the dc constructor for picts). Once I get the right… --- ## [Racket 8.6 in package repositories](https://racket.discourse.group/t/racket-8-6-in-package-repositories/1234)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [August 16, 2022, 1:07pm UTC](https://racket.discourse.group/t/racket-8-6-in-package-repositories/1234 "2022-08-16T13:07:50Z")
Racket is available from a variety of package repositories but they are not always kept up-to-date. The good news is thanks to a number of very kind and hardworking maintainers a number of package repositories have … --- ## [Racket v8.6 Released](https://racket.discourse.group/t/racket-v8-6-released/1222)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 5\ **Last updated:** [August 16, 2022, 7:17am UTC](https://racket.discourse.group/t/racket-v8-6-released/1222 "2022-08-16T07:17:50Z")
Racket version 8.6 is now available from https://download.racket-lang.org/ As of this release: Racket has an “equal-always?” primitive that equates values that will stay the same even if mutated. See equal-always? … --- ## [Where can i find solutions to exercises from the book "How to Design Classes"](https://racket.discourse.group/t/where-can-i-find-solutions-to-exercises-from-the-book-how-to-design-classes/1199)
**Author:** [@recursia](https://racket.discourse.group/u/recursia)\ **Replies:** 4\ **Last updated:** [August 15, 2022, 9:27pm UTC](https://racket.discourse.group/t/where-can-i-find-solutions-to-exercises-from-the-book-how-to-design-classes/1199 "2022-08-15T21:27:35Z")
English is not my main language,sorry for bad grammar. Programming is my hobby. I just finished HtDP. As a person,who have never programmed before,it gave me a lot. There is a book How to design Classes (same authors of… --- ## [What is the proper way to close a dialog box?](https://racket.discourse.group/t/what-is-the-proper-way-to-close-a-dialog-box/1233)
**Author:** [@dstorrs](https://racket.discourse.group/u/dstorrs)\ **Replies:** 2\ **Last updated:** [August 15, 2022, 6:49pm UTC](https://racket.discourse.group/t/what-is-the-proper-way-to-close-a-dialog-box/1233 "2022-08-15T18:49:05Z")
What is the proper way to close a dialog box? I admit I haven't read everything in the GUI library yet and I'm trying to learn as I go, but I feel like I must be overcomplicating something here. I looked at the code f… --- ## [New vs instantiate vs make-object](https://racket.discourse.group/t/new-vs-instantiate-vs-make-object/1230)
**Author:** [@dstorrs](https://racket.discourse.group/u/dstorrs)\ **Replies:** 2\ **Last updated:** [August 15, 2022, 4:26pm UTC](https://racket.discourse.group/t/new-vs-instantiate-vs-make-object/1230 "2022-08-15T16:26:30Z")
6.3 Creating Objects shows three separate methods for creating objects: (make-object class init-v ...) → object? (new class-expr (id by-name-expr) ...) (instantiate class-expr (by-pos-expr ...) (id by-name-expr) ...) I… --- ## [Recommended Approach to Locks](https://racket.discourse.group/t/recommended-approach-to-locks/1228)
**Author:** [@bsilver](https://racket.discourse.group/u/bsilver)\ **Replies:** 4\ **Last updated:** [August 15, 2022, 1:11pm UTC](https://racket.discourse.group/t/recommended-approach-to-locks/1228 "2022-08-15T13:11:23Z")
In some utilities I previously created using non-Racket languages, I'd track information referenced by multiple routines by using a struct with a R/W lock as a field; then I could create functions that would lock and def… --- ## [Omit the user from shared links](https://racket.discourse.group/t/omit-the-user-from-shared-links/1221)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 6\ **Last updated:** [August 11, 2022, 9:00pm UTC](https://racket.discourse.group/t/omit-the-user-from-shared-links/1221 "2022-08-11T21:00:09Z")
The sharing links that Discourse (or this Discourse instance?) uses all seem to have the user id appended as a query parameter. For example, if I go to the Racket 8.6 release thread and click on the link symbol of the fi… --- ## [Shared libraries that depend on each other?](https://racket.discourse.group/t/shared-libraries-that-depend-on-each-other/1037)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 10\ **Last updated:** [August 11, 2022, 7:42pm UTC](https://racket.discourse.group/t/shared-libraries-that-depend-on-each-other/1037 "2022-08-11T19:42:19Z")
WARNING: this question might very well have not a lot to do with Racket. We'll see. I'm working with a student, Alex MacLean, who's developing racket bindings for OpenFST. You can see the current version on the package … --- ## [Typed abstract methods / typed interfaces](https://racket.discourse.group/t/typed-abstract-methods-typed-interfaces/1197)
**Author:** [@scolobb](https://racket.discourse.group/u/scolobb)\ **Replies:** 7\ **Last updated:** [August 11, 2022, 4:42pm UTC](https://racket.discourse.group/t/typed-abstract-methods-typed-interfaces/1197 "2022-08-11T16:42:56Z")
Hello, I would like to define typed classes with abstract methods / interfaces. This is the approach I am going for at the moment: (define my-interface% (class object% (super-new) (: abstract-increment (-\> … --- ## [Research Papers](https://racket.discourse.group/t/research-papers/1220)
**Author:** [@simonls](https://racket.discourse.group/u/simonls)\ **Replies:** 1\ **Last updated:** [August 10, 2022, 11:13pm UTC](https://racket.discourse.group/t/research-papers/1220 "2022-08-10T23:13:25Z")
I am not an academic and I haven't read many papers, however sometimes I have and gotten different insights about some topics, getting a new perspective is enjoyable (if the paper in questions turns out to be easy to fol… --- ## [Racket community online](https://racket.discourse.group/t/racket-community-online/1203)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [August 10, 2022, 7:05pm UTC](https://racket.discourse.group/t/racket-community-online/1203 "2022-08-10T19:05:14Z")
I recently tried to work out where racket users communicate online. I thought it was interesting so I’m sharing here. — Places we find racket users. r/Racket has over 6904 subscribers https://twitter.com/racketlang … --- ## [Version 3.0 of Scheme+ for Racket](https://racket.discourse.group/t/version-3-0-of-scheme-for-racket/1218)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 3\ **Last updated:** [August 10, 2022, 9:05am UTC](https://racket.discourse.group/t/version-3-0-of-scheme-for-racket/1218 "2022-08-10T09:05:34Z")
Hi, i released a new version of Scheme+ , Version 3.0 add strings support and a few other enhancement. https://damien-mattei.github.io/Scheme-PLUS-for-Racket/Scheme+io.html https://pkgs.racket-lang.org/package/Scheme-… --- ## [Ubuntu 22.04 libssl 3 migration](https://racket.discourse.group/t/ubuntu-22-04-libssl-3-migration/942)
**Author:** [@evdubs](https://racket.discourse.group/u/evdubs)\ **Replies:** 3\ **Last updated:** [August 10, 2022, 3:23am UTC](https://racket.discourse.group/t/ubuntu-22-04-libssl-3-migration/942 "2022-08-10T03:23:38Z")
I recently upgraded to Ubuntu 22.04. Apparently, with 22.04, libssl has been moved to version 3.0. From that link: As some of you might have surmised, we’re planning to move to OpenSSL 3.0 for 22.04. This new major re… --- ## [Inheritance of parameterized typed classes](https://racket.discourse.group/t/inheritance-of-parameterized-typed-classes/1217)
**Author:** [@scolobb](https://racket.discourse.group/u/scolobb)\ **Replies:** 0\ **Last updated:** [August 8, 2022, 6:40pm UTC](https://racket.discourse.group/t/inheritance-of-parameterized-typed-classes/1217 "2022-08-08T18:40:40Z")
Hi, Suppose I have the following typed class: (define parent% (class object% #:forall (a) (super-new) (: show-me (-\> a Void)) (define/public (show-me x) (displayln x)))) What is the best way to say … --- ## [Racket distro packagers: please try building from a snapshot](https://racket.discourse.group/t/racket-distro-packagers-please-try-building-from-a-snapshot/1063)
**Author:** [@mflatt](https://racket.discourse.group/u/mflatt)\ **Replies:** 46\ **Last updated:** [August 7, 2022, 11:02pm UTC](https://racket.discourse.group/t/racket-distro-packagers-please-try-building-from-a-snapshot/1063 "2022-08-07T23:02:14Z")
This request is for anyone who packages the Racket implementation for installation by an OS package manager (as opposed to people who manage Racket packages in the sense of raco pkg). The upcoming v8.6 release will incl… [Previous page](https://racket.discourse.group/latest.md?page=54) [Next page](https://racket.discourse.group/latest.md?page=56)