# Latest **URL:** https://racket.discourse.group/latest.md?page=30 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 31 --- ## [How to install the "drracket-cmdline-args" (and other) plugin?](https://racket.discourse.group/t/how-to-install-the-drracket-cmdline-args-and-other-plugin/2892)
**Author:** [@frodeaux](https://racket.discourse.group/u/frodeaux)\ **Replies:** 2\ **Last updated:** [April 29, 2024, 6:44pm UTC](https://racket.discourse.group/t/how-to-install-the-drracket-cmdline-args-and-other-plugin/2892 "2024-04-29T18:44:13Z")
I had no problem locating a reference to this plugin for DrRacket, which allows specifying arguments to a script when it is run from DrRacket, but I can find nothing on where to obtain the plugin and how to install it! … --- ## [Using \`match\` ellipses on multiple elements?](https://racket.discourse.group/t/using-match-ellipses-on-multiple-elements/2891)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 1\ **Last updated:** [April 29, 2024, 1:08am UTC](https://racket.discourse.group/t/using-match-ellipses-on-multiple-elements/2891 "2024-04-29T01:08:19Z")
Context: getting creative with target language syntax in a PL course. I want to use match ellipses to apply to multiple elements. syntax/parse has a ~seq feature that handles this. Here's what I would like to write, ima… --- ## [Efficiently updating nested data structures in Racket](https://racket.discourse.group/t/efficiently-updating-nested-data-structures-in-racket/2877)
**Author:** [@rvdalen](https://racket.discourse.group/u/rvdalen)\ **Replies:** 12\ **Last updated:** [April 27, 2024, 8:09pm UTC](https://racket.discourse.group/t/efficiently-updating-nested-data-structures-in-racket/2877 "2024-04-27T20:09:06Z")
I am trying to write some code that updates immutable nested data structures. There does not seem to be good support for this in base Racket, and the internet seems to point to using the lens library for this. The lens… --- ## [How to evaluate code with function definitions in scribble](https://racket.discourse.group/t/how-to-evaluate-code-with-function-definitions-in-scribble/2888)
**Author:** [@oomaschloom](https://racket.discourse.group/u/oomaschloom)\ **Replies:** 2\ **Last updated:** [April 27, 2024, 4:53am UTC](https://racket.discourse.group/t/how-to-evaluate-code-with-function-definitions-in-scribble/2888 "2024-04-27T04:53:04Z")
Hi folks, I can't get an example to evaluate when it has define in it. I've tried lots of stuff. The example in the scribble documentation works, but that uses typed racket. I don't want to use typed racket: @examples\[… --- ## [Why isn't my macro hygienic?](https://racket.discourse.group/t/why-isnt-my-macro-hygienic/2881)
**Author:** [@xiaoyu2006](https://racket.discourse.group/u/xiaoyu2006)\ **Replies:** 8\ **Last updated:** [April 24, 2024, 2:15pm UTC](https://racket.discourse.group/t/why-isnt-my-macro-hygienic/2881 "2024-04-24T14:15:43Z")
Sorry for my newbie metaprogramming question. Say I have this macro: #lang racket/base (require (for-syntax racket/base)) ;; Depends on map, eval, quote (define-syntax (eval-emit stx) (syntax-case stx () \[(\_ exp… --- ## [Request for medium size examples in docs](https://racket.discourse.group/t/request-for-medium-size-examples-in-docs/2880)
**Author:** [@gus-massa](https://racket.discourse.group/u/gus-massa)\ **Replies:** 1\ **Last updated:** [April 24, 2024, 3:13am UTC](https://racket.discourse.group/t/request-for-medium-size-examples-in-docs/2880 "2024-04-24T03:13:59Z")
A few days ago, someone posted in Hacker News a language implemented in Racket. The docs of that langueage are quite complete and explain all the details. But when I see a post of a new language I want to see how it fee… --- ## [Turn-based games in typed Racket](https://racket.discourse.group/t/turn-based-games-in-typed-racket/2876)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 1\ **Last updated:** [April 23, 2024, 4:02pm UTC](https://racket.discourse.group/t/turn-based-games-in-typed-racket/2876 "2024-04-23T16:02:43Z")
How can one do something like \[Turn-Based Games\] Turn-Based Games in Typed Racket? The trouble is that each game one might implement requires its own types for Side, GameState, and MoveChoice. This presumably affects t… --- ## [Scheme+ special Racket edition](https://racket.discourse.group/t/scheme-special-racket-edition/2872)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 7\ **Last updated:** [April 23, 2024, 10:30am UTC](https://racket.discourse.group/t/scheme-special-racket-edition/2872 "2024-04-23T10:30:37Z")
Bonjour, i released Scheme+ for Racket v8.5, special Racket Edition :grin: Scheme+ for Racket v8.5 only compatible with Racket, using identifier-binding . New features: there is no more need to define a variable , t… --- ## [A global hash table where values are sets](https://racket.discourse.group/t/a-global-hash-table-where-values-are-sets/2677)
**Author:** [@jkleiser](https://racket.discourse.group/u/jkleiser)\ **Replies:** 10\ **Last updated:** [April 23, 2024, 3:17am UTC](https://racket.discourse.group/t/a-global-hash-table-where-values-are-sets/2677 "2024-04-23T03:17:11Z")
I have a text file of words, and I have found out how to read it, line by line. I extract the words from each line into a list, and those lists look like this: (w0 (w10 w11 w12 ...) (w20 w21 w22 ...)) As I read new line… --- ## [Is this expected output for call-with-composable-continuation?](https://racket.discourse.group/t/is-this-expected-output-for-call-with-composable-continuation/2875)
**Author:** [@Trung0246](https://racket.discourse.group/u/Trung0246)\ **Replies:** 2\ **Last updated:** [April 22, 2024, 9:32pm UTC](https://racket.discourse.group/t/is-this-expected-output-for-call-with-composable-continuation/2875 "2024-04-22T21:32:50Z")
\#lang racket/base (let (\[tag (make-continuation-prompt-tag)\]) (println "111") (println (string-append "222" (call-with-continuation-prompt (lambda () (let (\[data 0\]) (println (string-append "333" (c… --- ## [Surprisingly compact GUI programming](https://racket.discourse.group/t/surprisingly-compact-gui-programming/2823)
**Author:** [@rob](https://racket.discourse.group/u/rob)\ **Replies:** 3\ **Last updated:** [April 21, 2024, 11:14am UTC](https://racket.discourse.group/t/surprisingly-compact-gui-programming/2823 "2024-04-21T11:14:55Z")
Today, I came across Scheme and then Racket. The latter not only sounds interesting but looks so, too. On wikipedia (Racket features - Wikipedia) I found this neat interactive GUI demo, which shows toolkit API simplicity… --- ## [Transitive thread suspension for pausing computations made up of nested threads](https://racket.discourse.group/t/transitive-thread-suspension-for-pausing-computations-made-up-of-nested-threads/2867)
**Author:** [@gregr](https://racket.discourse.group/u/gregr)\ **Replies:** 7\ **Last updated:** [April 20, 2024, 2:18pm UTC](https://racket.discourse.group/t/transitive-thread-suspension-for-pausing-computations-made-up-of-nested-threads/2867 "2024-04-20T14:18:48Z")
I'm interested in running a pause-able computation as a separate thread that may itself spawn its own threads. I'd like to be able to pause the parent thread, and have it transitively pause the child threads it has spaw… --- ## [Qi discussion on effects tomorrow](https://racket.discourse.group/t/qi-discussion-on-effects-tomorrow/2870)
**Author:** [@countvajhula](https://racket.discourse.group/u/countvajhula)\ **Replies:** 0\ **Last updated:** [April 18, 2024, 11:30pm UTC](https://racket.discourse.group/t/qi-discussion-on-effects-tomorrow/2870 "2024-04-18T23:30:41Z")
Hi friends, Tomorrow, we're meeting to discuss Qi's handling of computational effects (i.e. anything other than function inputs and outputs - including I/O, state, etc.), and related things such as how user-extensibilit… --- ## [Navigation through (top-level) definitions in DrRacket](https://racket.discourse.group/t/navigation-through-top-level-definitions-in-drracket/2807)
**Author:** [@yossarian](https://racket.discourse.group/u/yossarian)\ **Replies:** 4\ **Last updated:** [April 16, 2024, 8:59pm UTC](https://racket.discourse.group/t/navigation-through-top-level-definitions-in-drracket/2807 "2024-04-16T20:59:14Z")
Hi, As a new user of (Dr)Racket I really miss a keyboard-based way to navigate through the different definitions of a .rkt file. I often forgot the name (or the existence) of a function that I have written before, and g… --- ## [Kill-safe cleanup of locally created threads](https://racket.discourse.group/t/kill-safe-cleanup-of-locally-created-threads/2862)
**Author:** [@gregr](https://racket.discourse.group/u/gregr)\ **Replies:** 1\ **Last updated:** [April 16, 2024, 12:25pm UTC](https://racket.discourse.group/t/kill-safe-cleanup-of-locally-created-threads/2862 "2024-04-16T12:25:10Z")
I'm interested in ensuring kill-safe cleanup of locally created threads in an arbitrary execution context. For instance, a user might run my code in a thread that is not managed by a custodian, which they then kill at a… --- ## [Main file name of module in https://pkgs.racket-lang.org/](https://racket.discourse.group/t/main-file-name-of-module-in-https-pkgs-racket-lang-org/2856)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 2\ **Last updated:** [April 10, 2024, 1:10pm UTC](https://racket.discourse.group/t/main-file-name-of-module-in-https-pkgs-racket-lang-org/2856 "2024-04-10T13:10:42Z")
Bonjour, i have a question about Racket's package. First due to another answer in a thread i have to say,once and only,that i do not respond to false answer about any of my project that would lead to polemic's long an… --- ## [2024 ICFP Programming Contest](https://racket.discourse.group/t/2024-icfp-programming-contest/2860)
**Author:** [@robby](https://racket.discourse.group/u/robby)\ **Replies:** 0\ **Last updated:** [April 8, 2024, 2:38pm UTC](https://racket.discourse.group/t/2024-icfp-programming-contest/2860 "2024-04-08T14:38:16Z")
From a post in another forum. Dear community, The ICFP programming contest 2024 is is held from Friday 28 June 2024 at 12:00 UTC to Monday 1 July 2024 at 12:00 UTC. There will be a lightning division, ending on Saturd… --- ## [Supporting displaced vectors & arrays in Racket](https://racket.discourse.group/t/supporting-displaced-vectors-arrays-in-racket/2858)
**Author:** [@mthom](https://racket.discourse.group/u/mthom)\ **Replies:** 3\ **Last updated:** [April 8, 2024, 12:42am UTC](https://racket.discourse.group/t/supporting-displaced-vectors-arrays-in-racket/2858 "2024-04-08T00:42:47Z")
Common Lisp has a nice feature for creating displaced arrays (or views, or slices, or ...) as exemplified in this interaction: CL-USER 29 \> (setq my-array (make-array '(2 2) :initial-contents '((a11 a12) (a13 a23)))) #2… --- ## [How to vertically-align number-entries in Scribble HTML bibliographies?](https://racket.discourse.group/t/how-to-vertically-align-number-entries-in-scribble-html-bibliographies/2650)
**Author:** [@encomer](https://racket.discourse.group/u/encomer)\ **Replies:** 1\ **Last updated:** [April 7, 2024, 11:07pm UTC](https://racket.discourse.group/t/how-to-vertically-align-number-entries-in-scribble-html-bibliographies/2650 "2024-04-07T23:07:21Z")
When rendering a scribble HTML document bibliography (using the number-style), the numbers at each entry are vertically aligned to the center. For example, with the following code: #lang scribble/manual @require\[scribl… --- ## [Does Ruckus still work?](https://racket.discourse.group/t/does-ruckus-still-work/2838)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 1\ **Last updated:** [April 6, 2024, 6:03pm UTC](https://racket.discourse.group/t/does-ruckus-still-work/2838 "2024-04-06T18:03:20Z")
When I run the sample first Rucku program as instructed in 2 Getting Your Ruckus On #lang ruckus (sphere 200) it fails. It writes out a lot of C code on my terminal, then complains generate-compile-and-link: error… --- ## [Dataframes using tabular-asa](https://racket.discourse.group/t/dataframes-using-tabular-asa/2854)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 5\ **Last updated:** [April 6, 2024, 1:47pm UTC](https://racket.discourse.group/t/dataframes-using-tabular-asa/2854 "2024-04-06T13:47:29Z")
I'm looking for a tables / dataframes implementation for Racket. I see tabular-asa, and a quick reading of the docs suggests that it's more or less exactly what I'm looking for. I do see a number of what appear to be doc… --- ## [Else: not allowed as an expression in: else](https://racket.discourse.group/t/else-not-allowed-as-an-expression-in-else/2848)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 9\ **Last updated:** [April 4, 2024, 4:05am UTC](https://racket.discourse.group/t/else-not-allowed-as-an-expression-in-else/2848 "2024-04-04T04:05:39Z")
\> (if #t 3 else) . else: not allowed as an expression in: else what is the real cause of the error? \> (if #t 3 toto) 3 in the context of a macro 'if' why is the 'else' reserved in scheme? (i would understand better th… --- ## [Using formlets from/with typed/racket, formlet-process and typing](https://racket.discourse.group/t/using-formlets-from-with-typed-racket-formlet-process-and-typing/2834)
**Author:** [@gabre](https://racket.discourse.group/u/gabre)\ **Replies:** 2\ **Last updated:** [March 30, 2024, 6:10pm UTC](https://racket.discourse.group/t/using-formlets-from-with-typed-racket-formlet-process-and-typing/2834 "2024-03-30T18:10:04Z")
I am trying to use formlets from typed/racket. I have the following racket module: #lang racket (require web-server/formlets/syntax) (require web-server/formlets/input) (require "blog-core-model.rkt") (provide new-p… --- ## [How to hilight non-racket code with Scribble?](https://racket.discourse.group/t/how-to-hilight-non-racket-code-with-scribble/2832)
**Author:** [@janus](https://racket.discourse.group/u/janus)\ **Replies:** 3\ **Last updated:** [March 30, 2024, 3:35am UTC](https://racket.discourse.group/t/how-to-hilight-non-racket-code-with-scribble/2832 "2024-03-30T03:35:34Z")
As a continuation to this StackOverflow question, I now want to hilight Idris2 code using Scribble. I like Scribble for the styling and the programmability in general, but the code of my documentation is not Scheme/Racke… --- ## [Break out of the cycle. What's the Racket way alternative?](https://racket.discourse.group/t/break-out-of-the-cycle-whats-the-racket-way-alternative/2814)
**Author:** [@Tyrn](https://racket.discourse.group/u/Tyrn)\ **Replies:** 34\ **Last updated:** [March 30, 2024, 2:53am UTC](https://racket.discourse.group/t/break-out-of-the-cycle-whats-the-racket-way-alternative/2814 "2024-03-30T02:53:04Z")
Hi, Iterating through a string is a piece of cake: (for (\[c "Hello"\]) (display c) (newline)) Even in a more sophisticated way: (define (list-chars str) (for (\[c str\] \[i (in-naturals)\]) (p… --- ## [Racket meet-up: Saturday, 6 April, 2024 at 18:00 UTC](https://racket.discourse.group/t/racket-meet-up-saturday-6-april-2024-at-18-00-utc/2843)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [March 29, 2024, 2:22pm UTC](https://racket.discourse.group/t/racket-meet-up-saturday-6-april-2024-at-18-00-utc/2843 "2024-03-29T14:22:18Z")
Racket meet-up: Saturday, 6 April, 2024 at 18:00 UTC In your timezone: 2024-04-06T18:00:00Z (UTC). (converter) At this meet-up: Show and tell News & rumours AOB This meet-up will be held at https://meet.jit.si/Rac… --- ## [July 2023 welcome](https://racket.discourse.group/t/july-2023-welcome/2842)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [July 22, 2023, 2:08pm UTC](https://racket.discourse.group/t/july-2023-welcome/2842 "2023-07-22T14:08:23Z")
Welcome to the new people who have just joined us via the invite link posted to the old racket users google group! This is not the only place discussion of Racket and Racket related topics takes place! While the most a… --- ## [A library for rearranging filter map join, etc. Clojure style](https://racket.discourse.group/t/a-library-for-rearranging-filter-map-join-etc-clojure-style/2841)
**Author:** [@Tyrn](https://racket.discourse.group/u/Tyrn)\ **Replies:** 7\ **Last updated:** [March 29, 2024, 6:19am UTC](https://racket.discourse.group/t/a-library-for-rearranging-filter-map-join-etc-clojure-style/2841 "2024-03-29T06:19:34Z")
Hi, I've seen a Racket library which allows for structuring filtering and mapping Clojure style, like this: (-\>\> (-\> (cs/replace authors #"\\"(?:\\\\.|\[^\\"\\\\\])\*\\"" " ") ;; Remove quoted substrings. (cs/repla… --- ## [Custom sort with a comparator](https://racket.discourse.group/t/custom-sort-with-a-comparator/2839)
**Author:** [@Tyrn](https://racket.discourse.group/u/Tyrn)\ **Replies:** 7\ **Last updated:** [March 27, 2024, 7:57pm UTC](https://racket.discourse.group/t/custom-sort-with-a-comparator/2839 "2024-03-27T19:57:53Z")
Hi, I want nothing fancy: a sort function (from a library), taking for arguments a list or a vector (of strings, in my case) and a comparator which I want to write myself according to my needs. The comparators are desc… --- ## [Importing in r6rs](https://racket.discourse.group/t/importing-in-r6rs/2840)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 1\ **Last updated:** [March 27, 2024, 12:18am UTC](https://racket.discourse.group/t/importing-in-r6rs/2840 "2024-03-27T00:18:43Z")
hello, how can i import a library in r6rs i have this working in Racket : (require "../Scheme-PLUS-for-Racket/main/Scheme-PLUS-for-Racket/src/array.rkt") Welcome to DrRacket, version 8.12 \[cs\]. Language: r6rs, with … [Previous page](https://racket.discourse.group/latest.md?page=29) [Next page](https://racket.discourse.group/latest.md?page=31)