# Questions & Answers **URL:** https://racket.discourse.group/c/questions/6.md?page=17 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 18 --- ## [Updating Racket](https://racket.discourse.group/t/updating-racket/2508)
**Author:** [@taeknibunadur](https://racket.discourse.group/u/taeknibunadur)\ **Replies:** 3\ **Last updated:** [November 17, 2023, 9:07am UTC](https://racket.discourse.group/t/updating-racket/2508 "2023-11-17T09:07:51Z")
I installed Racket on Linux using the bash script provided on the website. I'd like to update it to the latest version but am not sure how. Can anyone advise me please? --- ## [Rebuild package with dependancies problem](https://racket.discourse.group/t/rebuild-package-with-dependancies-problem/2506)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 3\ **Last updated:** [November 16, 2023, 5:35pm UTC](https://racket.discourse.group/t/rebuild-package-with-dependancies-problem/2506 "2023-11-16T17:35:11Z")
hello, i have two questions related to https://pkgs.racket-lang.org i put a module: Scheme-PLUS-for-Racket (it allow special syntax in Racket, see example: https://github.com/damien-mattei/AI\_Deep\_Learning/blob/main/e… --- ## [Package dependency problem](https://racket.discourse.group/t/package-dependency-problem/2490)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 5\ **Last updated:** [November 13, 2023, 6:32pm UTC](https://racket.discourse.group/t/package-dependency-problem/2490 "2023-11-13T18:32:22Z")
Hi, as an exercise I developed a data structure, a double linked ring. I create a github repository and I put it in the Racket catalog. I took Ring Buffer and Priority Queues as examples. Everything is fine except th… --- ## [Why would \`second\` being unbound identifier inside \`syntax-\>datum\`?](https://racket.discourse.group/t/why-would-second-being-unbound-identifier-inside-syntax-datum/2497)
**Author:** [@JohnSnow](https://racket.discourse.group/u/JohnSnow)\ **Replies:** 3\ **Last updated:** [November 13, 2023, 11:45am UTC](https://racket.discourse.group/t/why-would-second-being-unbound-identifier-inside-syntax-datum/2497 "2023-11-13T11:45:16Z")
In this program, ok and ok2 only differs at cadr & second #lang racket (second '(1 2 3)) (define-syntax (ok stx) (datum-\>syntax stx (let (\[s (syntax-\>datum stx)\]) (cadr s)))) (ok 1 2 3) (define-syntax (ok2 stx)… --- ## [Ubuntu Linux (22.04, and 23.10) and Racket documentation?](https://racket.discourse.group/t/ubuntu-linux-22-04-and-23-10-and-racket-documentation/2474)
**Author:** [@hrvoje064](https://racket.discourse.group/u/hrvoje064)\ **Replies:** 9\ **Last updated:** [November 10, 2023, 9:57pm UTC](https://racket.discourse.group/t/ubuntu-linux-22-04-and-23-10-and-racket-documentation/2474 "2023-11-10T21:57:46Z")
This, obviously is not a Racket problem, but maybe somebody has seen this before, and can offer a fix. Yesterday, and today, I installed several Linux distros on my computer, just to see if my math-quiz package works ev… --- ## [Help with a problem in the web apps tutorial in the Racket docs](https://racket.discourse.group/t/help-with-a-problem-in-the-web-apps-tutorial-in-the-racket-docs/2485)
**Author:** [@devonlepage](https://racket.discourse.group/u/devonlepage)\ **Replies:** 1\ **Last updated:** [November 9, 2023, 11:31pm UTC](https://racket.discourse.group/t/help-with-a-problem-in-the-web-apps-tutorial-in-the-racket-docs/2485 "2023-11-09T23:31:28Z")
I am a (noob) hobbyist programmer and have worked through the second edition of HtDP. Today I've been reading through Continue: Web Applications in Racket in the docs and I can't seem to get the iteration of the blog exa… --- ## [Typed web-server](https://racket.discourse.group/t/typed-web-server/2321)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 7\ **Last updated:** [November 7, 2023, 11:04pm UTC](https://racket.discourse.group/t/typed-web-server/2321 "2023-11-07T23:04:01Z")
Is there a typed Racket version of all the Racket web-server stuff? --- ## [Scribble possible to render to custom output format (Anki)?](https://racket.discourse.group/t/scribble-possible-to-render-to-custom-output-format-anki/2463)
**Author:** [@jegfish](https://racket.discourse.group/u/jegfish)\ **Replies:** 4\ **Last updated:** [November 7, 2023, 3:06pm UTC](https://racket.discourse.group/t/scribble-possible-to-render-to-custom-output-format-anki/2463 "2023-11-07T15:06:27Z")
I am looking to create a set of tutorials and am considering including Anki notes (spaced-repetition flashcards) alongside them to give readers an additional resource and facility to remember the information. I'm conside… --- ## [Help trying to figure out Racket! Newbie!](https://racket.discourse.group/t/help-trying-to-figure-out-racket-newbie/2465)
**Author:** [@Daler](https://racket.discourse.group/u/Daler)\ **Replies:** 3\ **Last updated:** [November 7, 2023, 1:06am UTC](https://racket.discourse.group/t/help-trying-to-figure-out-racket-newbie/2465 "2023-11-07T01:06:47Z")
Hello, I am currently working on a Racket programming project and I'm encountering some issues with my code. I have been trying to create a program that calculates the total duration of a Free-Fall Tower attraction, con… --- ## [Methods for passing messages to python scripts](https://racket.discourse.group/t/methods-for-passing-messages-to-python-scripts/2402)
**Author:** [@thrilway](https://racket.discourse.group/u/thrilway)\ **Replies:** 2\ **Last updated:** [November 6, 2023, 6:21pm UTC](https://racket.discourse.group/t/methods-for-passing-messages-to-python-scripts/2402 "2023-11-06T18:21:42Z")
I'm working on a racket project that involves parsing rss feeds. With no disrespect to Racket's xml package, I'd like to be able to use Python's feedparser library to handle the raw rss. Are there any common ways to, sa… --- ## [Automatically creating cstruct instances](https://racket.discourse.group/t/automatically-creating-cstruct-instances/2470)
**Author:** [@db7](https://racket.discourse.group/u/db7)\ **Replies:** 0\ **Last updated:** [November 6, 2023, 9:22am UTC](https://racket.discourse.group/t/automatically-creating-cstruct-instances/2470 "2023-11-06T09:22:40Z")
Hi there, is there any tool to automatically create instances of cstructs? I was trying to use contract-random-generate for that, but it doesn't seem to support it out of the box. In more detail, I have create several … --- ## [Looking for a free network port to listen on](https://racket.discourse.group/t/looking-for-a-free-network-port-to-listen-on/2446)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 4\ **Last updated:** [November 4, 2023, 5:52pm UTC](https://racket.discourse.group/t/looking-for-a-free-network-port-to-listen-on/2446 "2023-11-04T17:52:55Z")
In a server, I would like to suggest a free port number to listen on after I invite a client to connect to. I'm thinking of using high-numbered ports (maybe above 50000 or 60000 .. aren't there a bunch of ports there th… --- ## [Why does Typed Racket run faster when \`#:no-optimize\`?](https://racket.discourse.group/t/why-does-typed-racket-run-faster-when-no-optimize/2453)
**Author:** [@neteroster](https://racket.discourse.group/u/neteroster)\ **Replies:** 3\ **Last updated:** [November 3, 2023, 2:52pm UTC](https://racket.discourse.group/t/why-does-typed-racket-run-faster-when-no-optimize/2453 "2023-11-03T14:52:49Z")
Hello everyone, I am a beginner who has just started learning Racket. I am conducting some experiments with Typed Racket, and I have written the following code: #lang typed/racket (: benchmark-vector (-\> Integer Intege… --- ## [Why modules and when?](https://racket.discourse.group/t/why-modules-and-when/2447)
**Author:** [@thrilway](https://racket.discourse.group/u/thrilway)\ **Replies:** 5\ **Last updated:** [November 1, 2023, 10:04pm UTC](https://racket.discourse.group/t/why-modules-and-when/2447 "2023-11-01T22:04:54Z")
I'm working on a project in racket—a web app—and I'm wondering whether to make my individual rkt files into modules so the can be imported as, e.g.,(require users), or just leave them as is so they'd be imported as, e.g.,… --- ## [Failing tests reported by Racket repo](https://racket.discourse.group/t/failing-tests-reported-by-racket-repo/2434)
**Author:** [@hrvoje064](https://racket.discourse.group/u/hrvoje064)\ **Replies:** 5\ **Last updated:** [October 31, 2023, 2:49am UTC](https://racket.discourse.group/t/failing-tests-reported-by-racket-repo/2434 "2023-10-31T02:49:54Z")
My first try to create a package on racket-lang.org package repo, and I have a question (so far only one :grin:). I created a package there earlier today, and there were some orange remarks about license, about missing … --- ## [Path produced by define-runtime-path does not work on Win(11)](https://racket.discourse.group/t/path-produced-by-define-runtime-path-does-not-work-on-win-11/2442)
**Author:** [@hrvoje064](https://racket.discourse.group/u/hrvoje064)\ **Replies:** 2\ **Last updated:** [October 30, 2023, 4:36am UTC](https://racket.discourse.group/t/path-produced-by-define-runtime-path-does-not-work-on-win-11/2442 "2023-10-30T04:36:46Z")
Following the advice from one previous reply to my question, I'm now using (define-runtime-path ...), instead of (current-directory). This has solved one of my problems, namely, the program can now find "scribblings/math… --- ## [String formatting in Racket](https://racket.discourse.group/t/string-formatting-in-racket/2430)
**Author:** [@Sanjaya-Danushka](https://racket.discourse.group/u/Sanjaya-Danushka)\ **Replies:** 6\ **Last updated:** [October 28, 2023, 3:06am UTC](https://racket.discourse.group/t/string-formatting-in-racket/2430 "2023-10-28T03:06:53Z")
Hello, I'm new to racket. I want to learn format string like other languages. Chatgpt tells me these methods have. but it doesn't have.do you know how way to learn string format methods? Basic Format Types: ~a: Displa… --- ## [Error production in parser-tools/yacc](https://racket.discourse.group/t/error-production-in-parser-tools-yacc/2432)
**Author:** [@davidelettieri](https://racket.discourse.group/u/davidelettieri)\ **Replies:** 0\ **Last updated:** [October 27, 2023, 11:26am UTC](https://racket.discourse.group/t/error-production-in-parser-tools-yacc/2432 "2023-10-27T11:26:52Z")
I'm trying to learn how to use the package parser-tools-lib. There is one thing which I would like to understand but I'm not able to figure it out. These point in the docs An error production can be defined by provi… --- ## [Running Racket applications headless](https://racket.discourse.group/t/running-racket-applications-headless/2416)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 14\ **Last updated:** [October 24, 2023, 9:20pm UTC](https://racket.discourse.group/t/running-racket-applications-headless/2416 "2023-10-24T21:20:51Z")
Sometimes when you run a Racket application on a server or device with no display you get errors like Unable to init server: Could not connect: Connection refused Gtk initialization failed for display ":0" The solution… --- ## [How to initialize a cstruct that has an array?](https://racket.discourse.group/t/how-to-initialize-a-cstruct-that-has-an-array/2414)
**Author:** [@db7](https://racket.discourse.group/u/db7)\ **Replies:** 2\ **Last updated:** [October 24, 2023, 7:13am UTC](https://racket.discourse.group/t/how-to-initialize-a-cstruct-that-has-an-array/2414 "2023-10-24T07:13:12Z")
Hi all, I'd like to create a cstruct which has an array as one of its fields. For the sake of the example, let's say the array is an array of integers. When I try create a new instance of the cstruct, I don't know how t… --- ## [Commit used for package in DrDr run](https://racket.discourse.group/t/commit-used-for-package-in-drdr-run/2409)
**Author:** [@Laurent.O](https://racket.discourse.group/u/Laurent.O)\ **Replies:** 2\ **Last updated:** [October 21, 2023, 7:47pm UTC](https://racket.discourse.group/t/commit-used-for-package-in-drdr-run/2409 "2023-10-21T19:47:24Z")
Is there a way to know which commit was used for a package for a particular DrDr test run? I can see the general commit for racket/racket but not for the rest. --- ## [The true meaning of recursion in the SICP book](https://racket.discourse.group/t/the-true-meaning-of-recursion-in-the-sicp-book/2388)
**Author:** [@syafiqfadillah](https://racket.discourse.group/u/syafiqfadillah)\ **Replies:** 8\ **Last updated:** [October 21, 2023, 12:47pm UTC](https://racket.discourse.group/t/the-true-meaning-of-recursion-in-the-sicp-book/2388 "2023-10-21T12:47:00Z")
In chapter 1 subchapter 1.1.3 there is the sentence "First, observe that the first step dictates that in order to accomplish the evaluation process for a combination we must first perform the evaluation process on each… --- ## [Greater than sign in javascript script in Racket](https://racket.discourse.group/t/greater-than-sign-in-javascript-script-in-racket/2385)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 3\ **Last updated:** [October 16, 2023, 2:52pm UTC](https://racket.discourse.group/t/greater-than-sign-in-javascript-script-in-racket/2385 "2023-10-16T14:52:39Z")
I have trouble with the xexpr conversion of a script. I run a very simple case extracted from a much larger program: #lang web-server (require xml net/url) (xexpr-\>string '(script "SetTimeOut(() =\> {let d = new Dat… --- ## [How to match up macro-generated and user-defined identifiers?](https://racket.discourse.group/t/how-to-match-up-macro-generated-and-user-defined-identifiers/2379)
**Author:** [@pcn](https://racket.discourse.group/u/pcn)\ **Replies:** 2\ **Last updated:** [October 13, 2023, 4:11am UTC](https://racket.discourse.group/t/how-to-match-up-macro-generated-and-user-defined-identifiers/2379 "2023-10-13T04:11:19Z")
The question is likely very basic. I'm just rusty :grin: I'm trying to implement poor man's module that can be parameterized by types, using structs. An example is I can do something like: (define-signature (expr E) … --- ## [Parsack: cannot reference an identifier before its definition](https://racket.discourse.group/t/parsack-cannot-reference-an-identifier-before-its-definition/2349)
**Author:** [@indrjo](https://racket.discourse.group/u/indrjo)\ **Replies:** 2\ **Last updated:** [October 10, 2023, 12:08pm UTC](https://racket.discourse.group/t/parsack-cannot-reference-an-identifier-before-its-definition/2349 "2023-10-10T12:08:36Z")
I wrote some code in Haskell that I'd like to translate in Racket. It's about Parsec and Parsack. #lang racket (require parsack) (define quote-marks "'\\"\`") (define quoted-name (between (oneOf quote-marks) … --- ## [Passing command line arguments at compile-time?](https://racket.discourse.group/t/passing-command-line-arguments-at-compile-time/2368)
**Author:** [@rscho](https://racket.discourse.group/u/rscho)\ **Replies:** 2\ **Last updated:** [October 7, 2023, 1:48pm UTC](https://racket.discourse.group/t/passing-command-line-arguments-at-compile-time/2368 "2023-10-07T13:48:02Z")
Hi, I am writing a kind of constraint solver for a combinatorics problem involving bignums. The single best optimization I can perform is of course pruning the solution space as early as possible. So, I thought about i… --- ## [Testing changes to a plugin](https://racket.discourse.group/t/testing-changes-to-a-plugin/2364)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [October 7, 2023, 12:13pm UTC](https://racket.discourse.group/t/testing-changes-to-a-plugin/2364 "2023-10-07T12:13:16Z")
I'm finally getting round to submitting changes to the quickscript plugin that is included in Dr Racket. My guide to doing this is usually Tutorial: Contributing to Racket on the Racket Blog I used raco pkg update --de… --- ## [Minor DrRacket question](https://racket.discourse.group/t/minor-drracket-question/2363)
**Author:** [@lewisl](https://racket.discourse.group/u/lewisl)\ **Replies:** 14\ **Last updated:** [October 7, 2023, 12:09am UTC](https://racket.discourse.group/t/minor-drracket-question/2363 "2023-10-07T00:09:26Z")
Why doesn't DrRacket use xrepl for the interactions pane? xrepl is really brilliant and the repl in DrRacket is, politely, less brilliant. Nothing wrong with just using VS Code (or other) with xrepl in the integrated… --- ## [Trying to treat flvector as a collection: violates contract](https://racket.discourse.group/t/trying-to-treat-flvector-as-a-collection-violates-contract/2362)
**Author:** [@lewisl](https://racket.discourse.group/u/lewisl)\ **Replies:** 3\ **Last updated:** [October 6, 2023, 1:41pm UTC](https://racket.discourse.group/t/trying-to-treat-flvector-as-a-collection-violates-contract/2362 "2023-10-06T13:41:37Z")
I thought that data/collection was meant to allow a set of functions to be collection type agnostic. There must be some syntactic trick that is not documented for doing so. #lang racket/base (require racket/flonum) (re… --- ## [Racket Guide Module Basics typo](https://racket.discourse.group/t/racket-guide-module-basics-typo/2358)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 2\ **Last updated:** [October 5, 2023, 7:58am UTC](https://racket.discourse.group/t/racket-guide-module-basics-typo/2358 "2023-10-05T07:58:08Z")
Hello, I think I’ve found a typo in the racket guide. It’s at the bottom of the 6.1 Module Basics page: The text says raco exec instead of raco exe. Matteo [Previous page](https://racket.discourse.group/c/questions/6.md?page=16) [Next page](https://racket.discourse.group/c/questions/6.md?page=18)