# Latest **URL:** https://racket.discourse.group/latest.md?page=69 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 70 --- ## [Manuals that look the same - how?](https://racket.discourse.group/t/manuals-that-look-the-same-how/408)
**Author:** [@maketo](https://racket.discourse.group/u/maketo)\ **Replies:** 3\ **Last updated:** [December 11, 2021, 3:57pm UTC](https://racket.discourse.group/t/manuals-that-look-the-same-how/408 "2021-12-11T15:57:14Z")
Hello! I noticed that many Racket manuals, tutorials etc. online have the same look as the Racket official documentation. This may be a really dumb question but what is being used to produce these? Thanks! :slight\_smile: … --- ## [\`and/or\` accept values that are not boolean](https://racket.discourse.group/t/and-or-accept-values-that-are-not-boolean/407)
**Author:** [@dannypsnl](https://racket.discourse.group/u/dannypsnl)\ **Replies:** 4\ **Last updated:** [December 11, 2021, 2:34pm UTC](https://racket.discourse.group/t/and-or-accept-values-that-are-not-boolean/407 "2021-12-11T14:34:52Z")
For example, we can write down (and #t 1 0) ; 0 (and 1 #t 0) ; 0 (and 1 0 #t) ; #t (or 0 #t #f) ; 0 (or #t 0 #f) ; #t (or #t #f 0) ; #t I think these are two questions why they accept non-boolean? how should I interp… --- ## [Reader module affect by using \`require\`?](https://racket.discourse.group/t/reader-module-affect-by-using-require/401)
**Author:** [@dannypsnl](https://racket.discourse.group/u/dannypsnl)\ **Replies:** 6\ **Last updated:** [December 11, 2021, 1:07pm UTC](https://racket.discourse.group/t/reader-module-affect-by-using-require/401 "2021-12-11T13:07:07Z")
We can define a reader module language by ; literal/main.rkt (module reader racket (provide (rename-out \[literal-read read\] \[literal-read-syntax read-syntax\])) (define (literal-read in) ...) … --- ## [Is it possible to identify a procedure at expansion time?](https://racket.discourse.group/t/is-it-possible-to-identify-a-procedure-at-expansion-time/340)
**Author:** [@dstorrs](https://racket.discourse.group/u/dstorrs)\ **Replies:** 3\ **Last updated:** [December 11, 2021, 12:24am UTC](https://racket.discourse.group/t/is-it-possible-to-identify-a-procedure-at-expansion-time/340 "2021-12-11T00:24:18Z")
When writing macros, is it possible to identify procedures at expansion time? I think the answer is no, but I thought I'd check. In my try-catch module, the 'catch' clause expands out into a with-handlers clause. In o… --- ## [Book/chapter/paper club](https://racket.discourse.group/t/book-chapter-paper-club/158)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 10\ **Last updated:** [December 9, 2021, 8:42am UTC](https://racket.discourse.group/t/book-chapter-paper-club/158 "2021-12-09T08:42:14Z")
We're starting a book/chapter club! 1-December. Please reply with book/chapters/papers you would be interested in working through with others. How will it work? Reply here with your suggestions to get participants. M… --- ## [Mailing list mode no longer groups properly](https://racket.discourse.group/t/mailing-list-mode-no-longer-groups-properly/371)
**Author:** [@jryans](https://racket.discourse.group/u/jryans)\ **Replies:** 6\ **Last updated:** [December 8, 2021, 9:17pm UTC](https://racket.discourse.group/t/mailing-list-mode-no-longer-groups-properly/371 "2021-12-08T21:17:58Z")
I have been happily using the mailing list mode since it was enabled a few weeks back. However, something seems to have changed on or around Dec 6th (yesterday) such that my mail client is now acting as if each message i… --- ## [\[racketscript\] Dynamically require all racket files in a directory](https://racket.discourse.group/t/racketscript-dynamically-require-all-racket-files-in-a-directory/379)
**Author:** [@kurinoku](https://racket.discourse.group/u/kurinoku)\ **Replies:** 6\ **Last updated:** [December 8, 2021, 5:46pm UTC](https://racket.discourse.group/t/racketscript-dynamically-require-all-racket-files-in-a-directory/379 "2021-12-08T17:46:44Z")
I'm trying to dynamically require all rkt files in a directory without using any bindings of them, because they have conflicts. The tree is the following |- index.rkt |--- commands |- echo.rkt |- another-cmd.rkt … --- ## [GitHub workflow template that can be shared](https://racket.discourse.group/t/github-workflow-template-that-can-be-shared/393)
**Author:** [@dannypsnl](https://racket.discourse.group/u/dannypsnl)\ **Replies:** 2\ **Last updated:** [December 8, 2021, 4:24pm UTC](https://racket.discourse.group/t/github-workflow-template-that-can-be-shared/393 "2021-12-08T16:24:57Z")
To get this work, just fork GitHub - dannypsnl/.github to your account, then you should get the thing like the following --- ## [Plot with subscripts, superscripts, and more general latex in labels](https://racket.discourse.group/t/plot-with-subscripts-superscripts-and-more-general-latex-in-labels/373)
**Author:** [@marc](https://racket.discourse.group/u/marc)\ **Replies:** 6\ **Last updated:** [December 8, 2021, 10:54am UTC](https://racket.discourse.group/t/plot-with-subscripts-superscripts-and-more-general-latex-in-labels/373 "2021-12-08T10:54:09Z")
I use plot to create some mathematical graphs that go into papers otherwise written in Latex. For the graph I used today, all I needed was subscripts and a bar over letters. In Latex, it would be $s\_q$ and $\\bar{e}\_{x}$. … --- ## [Operator (re)definition and order of operations](https://racket.discourse.group/t/operator-re-definition-and-order-of-operations/368)
**Author:** [@decuser](https://racket.discourse.group/u/decuser)\ **Replies:** 14\ **Last updated:** [December 8, 2021, 4:10am UTC](https://racket.discourse.group/t/operator-re-definition-and-order-of-operations/368 "2021-12-08T04:10:30Z")
Given: #lang racket (\* (+ 2 (\* 4 6)) (+ 3 5 7)) (define + (\* 2 3)) + Why does dr racket complain about the combination starting at line 2, that: +: undefined; cannot reference an identifier before its definitio… --- ## [How can I test a procedure to determine a procedure was the result](https://racket.discourse.group/t/how-can-i-test-a-procedure-to-determine-a-procedure-was-the-result/367)
**Author:** [@decuser](https://racket.discourse.group/u/decuser)\ **Replies:** 5\ **Last updated:** [December 8, 2021, 2:59am UTC](https://racket.discourse.group/t/how-can-i-test-a-procedure-to-determine-a-procedure-was-the-result/367 "2021-12-08T02:59:12Z")
That is if I type: + #\ is the value of the evaluation. If I then: (check-expect '#\ +) it's bad syntax '#\<' or if I type (check-expect #\ +) it's the same. --- ## [Social Racket Council?](https://racket.discourse.group/t/social-racket-council/358)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 5\ **Last updated:** [December 8, 2021, 12:00am UTC](https://racket.discourse.group/t/social-racket-council/358 "2021-12-08T00:00:15Z")
Hi The idea of a ‘Social Racket Council‘ was raised in the Racket Town Hall at RacketCon (https://youtube.com/watch?v=73dDj\_z66qo&feature=share at 56:10) Any ideas on how this could work? --- ## [Is there anything like common lisp's describe and/or dissassemble?](https://racket.discourse.group/t/is-there-anything-like-common-lisps-describe-and-or-dissassemble/377)
**Author:** [@decuser](https://racket.discourse.group/u/decuser)\ **Replies:** 2\ **Last updated:** [December 7, 2021, 11:36pm UTC](https://racket.discourse.group/t/is-there-anything-like-common-lisps-describe-and-or-dissassemble/377 "2021-12-07T23:36:54Z")
In common lisp, it is possible to: (describe '+) which results in: + is the symbol +, lies in #\, is accessible in 14 packages ... ---snip #\ is a built-in system function. Argu… --- ## [Looking for system admin help for the package system](https://racket.discourse.group/t/looking-for-system-admin-help-for-the-package-system/375)
**Author:** [@samth](https://racket.discourse.group/u/samth)\ **Replies:** 0\ **Last updated:** [December 7, 2021, 8:32pm UTC](https://racket.discourse.group/t/looking-for-system-admin-help-for-the-package-system/375 "2021-12-07T20:32:20Z")
Currently, the implementation of https://pkgs.racket-lang.org as well as https://pkg-build.racket-lang.org (see Notes) is primarily maintained by Matthew Flatt, although much of it was originally written by Jay McCarthy … --- ## [Lazy, yet opportunistic streams](https://racket.discourse.group/t/lazy-yet-opportunistic-streams/369)
**Author:** [@dominik.pantucek](https://racket.discourse.group/u/dominik.pantucek)\ **Replies:** 1\ **Last updated:** [December 7, 2021, 9:27am UTC](https://racket.discourse.group/t/lazy-yet-opportunistic-streams/369 "2021-12-07T09:27:21Z")
While playing around with various ideas about how to approach rendering large (long) tables in uni-table\[1\], I realized that a lot of the processing work can be done lazily. However that would only postpone the actual wo… --- ## [Check-exn Reference entry question](https://racket.discourse.group/t/check-exn-reference-entry-question/362)
**Author:** [@rclayton](https://racket.discourse.group/u/rclayton)\ **Replies:** 4\ **Last updated:** [December 6, 2021, 10:45pm UTC](https://racket.discourse.group/t/check-exn-reference-entry-question/362 "2021-12-06T22:45:55Z")
The check-exn entry of the rackunit section of the Reference contains the sentence In the latter case, the exception raised must be an exn:fail?. This confuses me because exn:fail? is a predicate, not an exception. I t… --- ## [How to safely cast a \_pointer to \_bytes?](https://racket.discourse.group/t/how-to-safely-cast-a-pointer-to-bytes/364)
**Author:** [@kurinoku](https://racket.discourse.group/u/kurinoku)\ **Replies:** 6\ **Last updated:** [December 6, 2021, 7:26pm UTC](https://racket.discourse.group/t/how-to-safely-cast-a-pointer-to-bytes/364 "2021-12-06T19:26:07Z")
I'm using racket/draw/unsafe/cairo and a custom ffi for MagickWand C API. I have this definition, you can see the last parameter is \_bytes. (define-mwand MagickExportImagePixels (\_fun \_MagickWand-pointer \_size \_size \_s… --- ## [Contract for (λ (x . rest) x)](https://racket.discourse.group/t/contract-for-x-rest-x/325)
**Author:** [@badkins](https://racket.discourse.group/u/badkins)\ **Replies:** 2\ **Last updated:** [December 6, 2021, 7:21pm UTC](https://racket.discourse.group/t/contract-for-x-rest-x/325 "2021-12-06T19:21:01Z")
The documentation for -\>\* mentions a particular contract not matching (λ (x . rest) x) due to the rest args not being optional, but I was unable to find a contract that does match that function. What contract matches th… --- ## [Let over lambda and source location information](https://racket.discourse.group/t/let-over-lambda-and-source-location-information/306)
**Author:** [@cwebber](https://racket.discourse.group/u/cwebber)\ **Replies:** 3\ **Last updated:** [December 6, 2021, 3:47pm UTC](https://racket.discourse.group/t/let-over-lambda-and-source-location-information/306 "2021-12-06T15:47:04Z")
Take the following code: (require racket/match) (define-syntax-rule (methods\* \[(method-name method-args ...) body ...\] ... fallback) (let ((method-name (lambda (method-args ...)… --- ## [Performance optimizations (by Typed Racket, or otherwise)](https://racket.discourse.group/t/performance-optimizations-by-typed-racket-or-otherwise/350)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 2\ **Last updated:** [December 6, 2021, 3:32pm UTC](https://racket.discourse.group/t/performance-optimizations-by-typed-racket-or-otherwise/350 "2021-12-06T15:32:06Z")
In the Racket Slack someone asked whether the optimizations by Typed Racket can be done from standard Racket. The answer was "yes", since Typed Racket is just a library. :slight\_smile: This made me curious. What kind of… --- ## [Add dark mode compatible logo](https://racket.discourse.group/t/add-dark-mode-compatible-logo/50)
**Author:** [@pmatos](https://racket.discourse.group/u/pmatos)\ **Replies:** 17\ **Last updated:** [December 5, 2021, 8:54pm UTC](https://racket.discourse.group/t/add-dark-mode-compatible-logo/50 "2021-12-05T20:54:08Z")
It would be great to have a dark-mode compat logo. Currently it ends up looking like this: --- ## [Racket Meetup: Saturday December 4](https://racket.discourse.group/t/racket-meetup-saturday-december-4/130)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 5\ **Last updated:** [December 5, 2021, 5:49pm UTC](https://racket.discourse.group/t/racket-meetup-saturday-december-4/130 "2021-12-05T17:49:38Z")
Racket Meetup: Saturday December 4 2021-12-04T20:00:00Z (UTC) Where: https://gather.town/app/wH1EDG3McffLjrs0/racket-users When: First Saturday EVERY Month UTC: 20:00 (30 minutes but can overrun) The next meetup is … --- ## [Scheduling the next Racket Meet-up in January 2022](https://racket.discourse.group/t/scheduling-the-next-racket-meet-up-in-january-2022/357)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [December 5, 2021, 3:47pm UTC](https://racket.discourse.group/t/scheduling-the-next-racket-meet-up-in-january-2022/357 "2021-12-05T15:47:59Z")
Two questions regarding the scheduling of the next Racket meet-up. New Year’s Day might be difficult for some people, or it might be fine with everyone. I don’t want to make assumptions please let us know, either with t… --- ## [Pict color specifications](https://racket.discourse.group/t/pict-color-specifications/356)
**Author:** [@dominik.pantucek](https://racket.discourse.group/u/dominik.pantucek)\ **Replies:** 4\ **Last updated:** [December 5, 2021, 3:28pm UTC](https://racket.discourse.group/t/pict-color-specifications/356 "2021-12-05T15:28:35Z")
I am a bit confused about how the colors are specified in the pict package. The colorize\[1\] procedure allows any of the color/c\[2\] values to be used (although it is explicitly written in the documented contract what that… --- ## [Naming convention for X vs. a procedure that returns X](https://racket.discourse.group/t/naming-convention-for-x-vs-a-procedure-that-returns-x/299)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 5\ **Last updated:** [December 4, 2021, 10:37pm UTC](https://racket.discourse.group/t/naming-convention-for-x-vs-a-procedure-that-returns-x/299 "2021-12-04T22:37:13Z")
In my code, I sometimes have a pattern (define ... (define func-result (func ...)) ...) That is, I call a function func and want to bind the result of the function call to a local identifier. Now, in many cases it … --- ## [Where's the Racket wiki?](https://racket.discourse.group/t/wheres-the-racket-wiki/351)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 4\ **Last updated:** [December 4, 2021, 4:56pm UTC](https://racket.discourse.group/t/wheres-the-racket-wiki/351 "2021-12-04T16:56:46Z")
I'm sure I've seen the Racket wiki before. But I don't see it mentioned on the front page https://racket-lang.org/ under "Vibrant Community" nor under "Racket, the Ecosystem." When I do a web search racket programmi… --- ## [Calendar of Events for 2022](https://racket.discourse.group/t/calendar-of-events-for-2022/352)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [December 4, 2021, 3:10pm UTC](https://racket.discourse.group/t/calendar-of-events-for-2022/352 "2021-12-04T15:10:11Z")
Hi I’ve created a draft page on the Wiki: I’m hoping to discuss events at the Meet-up Would you like to see? What works? What doesn’t? What should be included? (the draft is liberal in that is includes events that … --- ## [Calendar plugin](https://racket.discourse.group/t/calendar-plugin/342)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 5\ **Last updated:** [December 4, 2021, 3:59am UTC](https://racket.discourse.group/t/calendar-plugin/342 "2021-12-04T03:59:48Z")
Hi, Can we trial the official calendar plugin? It was suggested that this could be done in a private ‘Events’ topic while working it out so people could opt in to joining it prior to launch. Bw Stephen --- ## [New chapter in "Logic and Computation Intertwined"](https://racket.discourse.group/t/new-chapter-in-logic-and-computation-intertwined/338)
**Author:** [@plragde](https://racket.discourse.group/u/plragde)\ **Replies:** 5\ **Last updated:** [December 3, 2021, 9:54pm UTC](https://racket.discourse.group/t/new-chapter-in-logic-and-computation-intertwined/338 "2021-12-03T21:54:33Z")
This is perhaps tangential, but my flânerie "Logic and Computation Intertwined" uses Racket as its implementation language. Students learn about propositional and predicate logic by using Racket to construct a small proo… --- ## [Slack and discord integration?](https://racket.discourse.group/t/slack-and-discord-integration/341)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [December 3, 2021, 9:15pm UTC](https://racket.discourse.group/t/slack-and-discord-integration/341 "2021-12-03T21:15:43Z")
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