# Latest **URL:** https://racket.discourse.group/latest.md?page=24 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 25 --- ## [Enjoying the 14th RacketCon? please consider supporting Racket](https://racket.discourse.group/t/enjoying-the-14th-racketcon-please-consider-supporting-racket/3201)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 3\ **Last updated:** [October 7, 2024, 11:27pm UTC](https://racket.discourse.group/t/enjoying-the-14th-racketcon-please-consider-supporting-racket/3201 "2024-10-07T23:27:11Z")
If you are enjoying the 14th RacketCon please consider supporting the Racket project and community. Donations, both in-kind and monetary, are used for hosting community infrastructure, administration, educational outrea… --- ## [Racket v8.15 Release Thread](https://racket.discourse.group/t/racket-v8-15-release-thread/3204)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 0\ **Last updated:** [October 7, 2024, 8:22pm UTC](https://racket.discourse.group/t/racket-v8-15-release-thread/3204 "2024-10-07T20:22:01Z")
The release process for v8.15 will begin in about four days. If you have any new features that you want in and are relatively close to to being done, now is a good time to do that. Upcoming dates: - 11th: Branch day, … --- ## [WeScheme Editor](https://racket.discourse.group/t/wescheme-editor/3202)
**Author:** [@rogert](https://racket.discourse.group/u/rogert)\ **Replies:** 5\ **Last updated:** [October 7, 2024, 2:36pm UTC](https://racket.discourse.group/t/wescheme-editor/3202 "2024-10-07T14:36:05Z")
Attempting to use the WeScheme Editor at https://www.bootstrapworld.org/materials/fall2024/en-us/lessons/hoc-wescheme-intro/index.shtml# , the second page states In the editor, we've written a simple program in the D… --- ## [Difference Lists and Racket](https://racket.discourse.group/t/difference-lists-and-racket/3184)
**Author:** [@shawnw](https://racket.discourse.group/u/shawnw)\ **Replies:** 3\ **Last updated:** [October 6, 2024, 10:07pm UTC](https://racket.discourse.group/t/difference-lists-and-racket/3184 "2024-10-06T22:07:11Z")
Something I've been playing with and wanted to share. If you're building up a final list by appending intermediate ones together, it's easy to get quadratic behavior if you're not careful - appending to the end of a con… --- ## [Everyone is welcome to join us for the Racket/Con ONLINE meet-up: Saturday, 5 October, 2024 at 9:45am RacketCon (Seattle) time](https://racket.discourse.group/t/everyone-is-welcome-to-join-us-for-the-racket-con-online-meet-up-saturday-5-october-2024-at-9-45am-racketcon-seattle-time/3199)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [October 5, 2024, 9:11am UTC](https://racket.discourse.group/t/everyone-is-welcome-to-join-us-for-the-racket-con-online-meet-up-saturday-5-october-2024-at-9-45am-racketcon-seattle-time/3199 "2024-10-05T09:11:09Z")
Everyone is welcome to join us on Jitsi Meet for the Racket meet-up: Saturday, 5 October, 2024 at 9:45am RacketCon (Seattle) time - we will also meet at the usual 18:00 UTC time. In your timezone: 2024-10-05T16:45:00Z (… --- ## [Pratt parsing is so easy, it should be criminal!](https://racket.discourse.group/t/pratt-parsing-is-so-easy-it-should-be-criminal/3197)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 0\ **Last updated:** [October 3, 2024, 9:04pm UTC](https://racket.discourse.group/t/pratt-parsing-is-so-easy-it-should-be-criminal/3197 "2024-10-03T21:04:19Z")
Hi, Racket Discourse. I recently had to implement a parser for converting infix to prefix notation, with the purpose of converting user-provided queries into an expression that could be evaled to produce the desired res… --- ## [2 versions of Racket code shared accross network disks](https://racket.discourse.group/t/2-versions-of-racket-code-shared-accross-network-disks/3196)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [October 3, 2024, 9:04am UTC](https://racket.discourse.group/t/2-versions-of-racket-code-shared-accross-network-disks/3196 "2024-10-03T09:04:27Z")
hello, i share on a Dropbox my Racket code between MacOS and Linux (and even i have 2 versions of Racket different) so i got message: loading code: version mismatch expected: "8.13" found: "8.14" in: /Users/matte… --- ## [Confused about tab-panel usage with mred-designer's code](https://racket.discourse.group/t/confused-about-tab-panel-usage-with-mred-designers-code/3189)
**Author:** [@shakeshuck](https://racket.discourse.group/u/shakeshuck)\ **Replies:** 2\ **Last updated:** [October 1, 2024, 10:43pm UTC](https://racket.discourse.group/t/confused-about-tab-panel-usage-with-mred-designers-code/3189 "2024-10-01T22:43:23Z")
I'm using mred-designer, and am confused as to how I am supposed to get children under the appropriate tabs. All the areas I have added appear under tabs-panel, but under the first tab only. The generated code looks like… --- ## [A typewriter problem (and colors...)](https://racket.discourse.group/t/a-typewriter-problem-and-colors/3190)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [October 1, 2024, 10:54am UTC](https://racket.discourse.group/t/a-typewriter-problem-and-colors/3190 "2024-10-01T10:54:11Z")
hello, this could be a joke (and i like that :wink: ) but it is not one... i have a SRFI-105 curly infix reader that works in Racket GUI and CLI (command line interface) too... but for a weird reason the same code doe… --- ## [Predicate Inconsistency in with List, Listof in Polymorphic Functions](https://racket.discourse.group/t/predicate-inconsistency-in-with-list-listof-in-polymorphic-functions/3187)
**Author:** [@wolfraam](https://racket.discourse.group/u/wolfraam)\ **Replies:** 3\ **Last updated:** [September 28, 2024, 11:50pm UTC](https://racket.discourse.group/t/predicate-inconsistency-in-with-list-listof-in-polymorphic-functions/3187 "2024-09-28T23:50:04Z")
Hello, If I define a function taking a heterogeneous list (List A ... A) and try to coerce the argument to a pair with (assert lst pair?) or an unless guard, the program typechecks, but the assertion fails even when I p… --- ## [Writing to output port from GUI callback function stalls event handling on windows](https://racket.discourse.group/t/writing-to-output-port-from-gui-callback-function-stalls-event-handling-on-windows/3185)
**Author:** [@jjsimpso](https://racket.discourse.group/u/jjsimpso)\ **Replies:** 3\ **Last updated:** [September 28, 2024, 5:49pm UTC](https://racket.discourse.group/t/writing-to-output-port-from-gui-callback-function-stalls-event-handling-on-windows/3185 "2024-09-28T17:49:05Z")
I've run into a strange issue while testing my application on Windows. This does not occur on Linux. It is a racket/gui app that uses a custom subclass of canvas% that I wrote. When dragging the scroll bar on Windows, i… --- ## [Can this contract error be easily improved?](https://racket.discourse.group/t/can-this-contract-error-be-easily-improved/3181)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 3\ **Last updated:** [September 27, 2024, 10:08pm UTC](https://racket.discourse.group/t/can-this-contract-error-be-easily-improved/3181 "2024-09-27T22:08:48Z")
Here's a program: #lang racket (define foo-contract (-\> integer? day)) (struct day (a b c)) Note that I've omitted the intended ? for the day? predicate in the contract, writing instead day. Oops. The error it sig… --- ## [Infinite pretty-print width bug](https://racket.discourse.group/t/infinite-pretty-print-width-bug/3178)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 3\ **Last updated:** [September 26, 2024, 11:51pm UTC](https://racket.discourse.group/t/infinite-pretty-print-width-bug/3178 "2024-09-26T23:51:31Z")
In class today I ran across an extremely-difficult-to-reproduce error which nevertheless comes with an error message that might make it possible to repair anyway. Here's a screenshot, showing a program and the result of… --- ## [RacketCon 2024 - it’s not to late to get your tickets](https://racket.discourse.group/t/racketcon-2024-it-s-not-to-late-to-get-your-tickets/3183)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [September 26, 2024, 10:32pm UTC](https://racket.discourse.group/t/racketcon-2024-it-s-not-to-late-to-get-your-tickets/3183 "2024-09-26T22:32:35Z")
RacketCon 2024 - it’s not to late to get your tickets Celebrating 40 years of magic with Hal Abelson & Gerald Sussman at the (fourteenth RacketCon) October 5-6, 2024, University of Washington Featuring Lisp legend G… --- ## [Announcement: Custom Resyntax Rules](https://racket.discourse.group/t/announcement-custom-resyntax-rules/3176)
**Author:** [@notjack](https://racket.discourse.group/u/notjack)\ **Replies:** 0\ **Last updated:** [September 24, 2024, 12:32am UTC](https://racket.discourse.group/t/announcement-custom-resyntax-rules/3176 "2024-09-24T00:32:25Z")
Resyntax now has a public API for creating your own refactoring rules. The API is based on syntax-parse. It ought to be familiar to anyone used to writing macros with define-syntax-parse-rule. You can use your custom rul… --- ## [Get ready for the (fourteenth RacketCon) celebrating 40 years of magic](https://racket.discourse.group/t/get-ready-for-the-fourteenth-racketcon-celebrating-40-years-of-magic/3171)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [September 14, 2024, 3:43pm UTC](https://racket.discourse.group/t/get-ready-for-the-fourteenth-racketcon-celebrating-40-years-of-magic/3171 "2024-09-14T15:43:19Z")
Get ready for the (fourteenth RacketCon) Celebrating 40 years of magic with Hal Abelson & Gerald Sussman, and featuring Lisp legend Gregor Kiczales October 5-6, 2024 Details and tickets at https://con.racket-lang.o… --- ## ["The Little Learner" book club](https://racket.discourse.group/t/the-little-learner-book-club/3173)
**Author:** [@shadgregory](https://racket.discourse.group/u/shadgregory)\ **Replies:** 3\ **Last updated:** [September 22, 2024, 8:56am UTC](https://racket.discourse.group/t/the-little-learner-book-club/3173 "2024-09-22T08:56:53Z")
"The Little Learner" book club continues! We will meet online at: https://meet.jit.si/thelittlelearner We plan to cover chapters 4-6. Everybody is invited! --- ## [Scheme+ v9.3 released](https://racket.discourse.group/t/scheme-v9-3-released/3175)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [September 22, 2024, 8:53am UTC](https://racket.discourse.group/t/scheme-v9-3-released/3175 "2024-09-22T08:53:44Z")
hello, i released an updated version of Scheme+ for Racket, fully written with modules. There is no more needs of external parser (unless for SRFI 105 curly infix which is now in a separate package) as the syntactic jo… --- ## [Getting going with gsl-integration](https://racket.discourse.group/t/getting-going-with-gsl-integration/3164)
**Author:** [@AlexG](https://racket.discourse.group/u/AlexG)\ **Replies:** 4\ **Last updated:** [September 21, 2024, 1:32am UTC](https://racket.discourse.group/t/getting-going-with-gsl-integration/3164 "2024-09-21T01:32:32Z")
I am trying to set up the gsl-integration package. I have installed the package itself, and I have (I think) installed the GNU GSL libraries too. I am using DrRacket 8.6 under Ubuntu 22.04 I tried to install the C lib… --- ## [I want to break free :-) : break in my code with call/cc does not return a value](https://racket.discourse.group/t/i-want-to-break-free-break-in-my-code-with-call-cc-does-not-return-a-value/3169)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 5\ **Last updated:** [September 19, 2024, 9:48pm UTC](https://racket.discourse.group/t/i-want-to-break-free-break-in-my-code-with-call-cc-does-not-return-a-value/3169 "2024-09-19T21:48:52Z")
i have for (for\_next\_step.rkt) that allow C style for with break and continue. Example: Welcome to DrRacket, version 8.14 \[cs\]. Language: racket, with debugging; memory limit: 8192 MB. \> (require Scheme+/for\_next\_step)… --- ## [For/sum in typed/racket](https://racket.discourse.group/t/for-sum-in-typed-racket/3166)
**Author:** [@ken](https://racket.discourse.group/u/ken)\ **Replies:** 10\ **Last updated:** [September 17, 2024, 6:40pm UTC](https://racket.discourse.group/t/for-sum-in-typed-racket/3166 "2024-09-17T18:40:25Z")
I'm experimenting with typed/racket to see if it can speed up some lengthy numerical calculations. As a first step, I tried to sum all the square roots up to a million, first in plain Racket: (for/sum (\[i 1000000\]) (… --- ## [Importing all struct features? \[inverse of struct-out\]](https://racket.discourse.group/t/importing-all-struct-features-inverse-of-struct-out/3104)
**Author:** [@Greg\_Davidson](https://racket.discourse.group/u/Greg_Davidson)\ **Replies:** 2\ **Last updated:** [September 12, 2024, 7:03pm UTC](https://racket.discourse.group/t/importing-all-struct-features-inverse-of-struct-out/3104 "2024-09-12T19:03:09Z")
I can conveniently provide all of a structure's features, including its id, with a struct-out clause inside of a provide form. Is there an inverse for importing such in a require form without importing everything unrela… --- ## [\[ANN\] Doom Emacs supports Racket Mode's racket-hash-lang-mode](https://racket.discourse.group/t/ann-doom-emacs-supports-racket-modes-racket-hash-lang-mode/3167)
**Author:** [@sorawee](https://racket.discourse.group/u/sorawee)\ **Replies:** 0\ **Last updated:** [September 12, 2024, 12:15am UTC](https://racket.discourse.group/t/ann-doom-emacs-supports-racket-modes-racket-hash-lang-mode/3167 "2024-09-12T00:15:23Z")
Doom Emacs recently supports racket-hash-lang-mode in Racket Mode via the +hash-lang flag. Rhombus files are now also recognized by default. --- ## ["path+anchor-\>tag", or, get bluebox given path+anchor](https://racket.discourse.group/t/path-anchor-tag-or-get-bluebox-given-path-anchor/3165)
**Author:** [@greghendershott](https://racket.discourse.group/u/greghendershott)\ **Replies:** 1\ **Last updated:** [September 11, 2024, 7:21pm UTC](https://racket.discourse.group/t/path-anchor-tag-or-get-bluebox-given-path-anchor/3165 "2024-09-11T19:21:00Z")
There exists xref-tag-\>path+anchor. I don't see the reverse -- anything like "xref-path+anchor-\>tag". Is it possible for me to write this myself, and if so, how? Why I ask: Given a documentation path + anchor, I want… --- ## [Hard to get Packages without documentation](https://racket.discourse.group/t/hard-to-get-packages-without-documentation/3157)
**Author:** [@Zeb](https://racket.discourse.group/u/Zeb)\ **Replies:** 9\ **Last updated:** [September 11, 2024, 5:02am UTC](https://racket.discourse.group/t/hard-to-get-packages-without-documentation/3157 "2024-09-11T05:02:15Z")
I want to talk about getting packages installed without their docs. I tried the binary and binary lib options of raco setup and they always tell me the package isn't compatible. I've often had to resort to manually stri… --- ## [Autumn Lisp Game Jam 2024](https://racket.discourse.group/t/autumn-lisp-game-jam-2024/3163)
**Author:** [@Kamen](https://racket.discourse.group/u/Kamen)\ **Replies:** 0\ **Last updated:** [September 10, 2024, 4:36pm UTC](https://racket.discourse.group/t/autumn-lisp-game-jam-2024/3163 "2024-09-10T16:36:28Z")
Dave Thompson (of Guile Chickadee, The Spritely Institute, and - tips hat - Guile Hoot fame) has announced the 2024 Autumn Lisp Game Jam over at itch\_io: In the opinion of this Racketeer wannabe, the Lisp Game Jam is … --- ## [Only 25 days till RacketCon](https://racket.discourse.group/t/only-25-days-till-racketcon/3162)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [September 10, 2024, 4:07pm UTC](https://racket.discourse.group/t/only-25-days-till-racketcon/3162 "2024-09-10T16:07:09Z")
25 DAYS TILL RacketCon https://con.racket-lang.org/ https://www.timeanddate.com/countdown/launch?iso=20241005T0830&p0=234&msg=RacketCon+2024&ud=2&font=cursive&csz=1 To register, buy a ticket via Eventbrite. If you … --- ## [The fern fractal](https://racket.discourse.group/t/the-fern-fractal/3160)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 0\ **Last updated:** [September 10, 2024, 5:16am UTC](https://racket.discourse.group/t/the-fern-fractal/3160 "2024-09-10T05:16:47Z")
Hi, a few months ago I developed the fern fractal. If you are interested or just curious you can find the code and the picture in the documentation of the simple-svg package made by Chen Xiao in the showcase chapter. M… --- ## [Outdated mirror upstream](https://racket.discourse.group/t/outdated-mirror-upstream/3129)
**Author:** [@HarryChen](https://racket.discourse.group/u/HarryChen)\ **Replies:** 2\ **Last updated:** [September 10, 2024, 5:06am UTC](https://racket.discourse.group/t/outdated-mirror-upstream/3129 "2024-09-10T05:06:30Z")
I am the administrator of https://mirrors.tuna.tsinghua.edu.cn. We (and many other mirror sites) synchronize racket-installer from rsync://mirror.csclub.uwaterloo.ca/racket/ periodically. We have received a report from … --- ## [Streams questions](https://racket.discourse.group/t/streams-questions/3147)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 22\ **Last updated:** [September 9, 2024, 11:49am UTC](https://racket.discourse.group/t/streams-questions/3147 "2024-09-09T11:49:23Z")
Hi, I need to work with streams, I'm reading the racket reference and I have some questions. Why stream-map doesn't accept more than one stream? I read that the one in SRFI-41 does. Why the function f is sometimes pro… [Previous page](https://racket.discourse.group/latest.md?page=23) [Next page](https://racket.discourse.group/latest.md?page=25)