# Latest **URL:** https://racket.discourse.group/latest.md?page=20 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 21 --- ## [Advent 2024: Day ι (Translate DrRacket interface in your language)](https://racket.discourse.group/t/advent-2024-day-translate-drracket-interface-in-your-language/3407)
**Author:** [@al\_shopov](https://racket.discourse.group/u/al_shopov)\ **Replies:** 3\ **Last updated:** [December 15, 2024, 6:18am UTC](https://racket.discourse.group/t/advent-2024-day-translate-drracket-interface-in-your-language/3407 "2024-12-15T06:18:52Z")
Hello all, This is a short, practical guide how you can translate the interface of DrRacket in your language. As I am currently studying Scribl - it will be added as a pull request for the documentation in string-const… --- ## [New Racket Deep Learning Library](https://racket.discourse.group/t/new-racket-deep-learning-library/2953)
**Author:** [@0x7fmarq](https://racket.discourse.group/u/0x7fmarq)\ **Replies:** 8\ **Last updated:** [December 13, 2024, 12:09pm UTC](https://racket.discourse.group/t/new-racket-deep-learning-library/2953 "2024-12-13T12:09:13Z")
Hi everyone, I'd like to show off MIND, (GitHub - dev-null321/MIND: Deep learning library) which is a deep learning library I wrote in Racket. It can be used to make simple FNN systems. The library includes essential co… --- ## [Advent 2024: Day 13 (Fern Fractal)](https://racket.discourse.group/t/advent-2024-day-13-fern-fractal/3411)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 0\ **Last updated:** [December 13, 2024, 12:03pm UTC](https://racket.discourse.group/t/advent-2024-day-13-fern-fractal/3411 "2024-12-13T12:03:11Z")
Hello, I saw this fractal many years ago on Usenet in comp.lang.scheme. It was made with turtles, but I made it with complex numbers. You can find the code in the documentation of the simple-svg package made by Chen… --- ## [Using Racket In A Windows Powershell Script](https://racket.discourse.group/t/using-racket-in-a-windows-powershell-script/3410)
**Author:** [@OldDutchCap](https://racket.discourse.group/u/OldDutchCap)\ **Replies:** 0\ **Last updated:** [December 12, 2024, 10:05pm UTC](https://racket.discourse.group/t/using-racket-in-a-windows-powershell-script/3410 "2024-12-12T22:05:05Z")
I have worked on Windows for some time and as such I've had some exposure to Powershell. I know it's possible to use Racket in Windows Batch files but Windows Batch files are rather primitive compared with Powershell. A… --- ## [What kind of \`with\`s have you come up with?](https://racket.discourse.group/t/what-kind-of-with-s-have-you-come-up-with/3360)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 14\ **Last updated:** [December 12, 2024, 6:21pm UTC](https://racket.discourse.group/t/what-kind-of-with-s-have-you-come-up-with/3360 "2024-12-12T18:21:22Z")
Hi, Racket Discourse. Lol, I accidentally posted the deleted entry prematurely trying to start this one. Such embarrass. Much wow. Never the mind. I read a post the other day regarding a with-gunzip helper, which I end… --- ## [\#langs that Fit in Your Head](https://racket.discourse.group/t/langs-that-fit-in-your-head/3404)
**Author:** [@countvajhula](https://racket.discourse.group/u/countvajhula)\ **Replies:** 4\ **Last updated:** [December 12, 2024, 3:42am UTC](https://racket.discourse.group/t/langs-that-fit-in-your-head/3404 "2024-12-12T03:42:07Z")
Here's #langs that Fit in Your Head, a post about writing "small" languages. The irony is that I'm not sure this blog post fits in your head :laughing: . Enjoy, and happy Advent of Racket Day 8! --- ## [Copy-file and upi/cp fail to copy the entire file](https://racket.discourse.group/t/copy-file-and-upi-cp-fail-to-copy-the-entire-file/3406)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 3\ **Last updated:** [December 10, 2024, 11:16am UTC](https://racket.discourse.group/t/copy-file-and-upi-cp-fail-to-copy-the-entire-file/3406 "2024-12-10T11:16:39Z")
hello, a so weird error i do not expect answers but who knows.... when copying a file with copy-file or upi/cp: https://docs.racket-lang.org/upi/upi-cp.html it is truncated near the end (496kb file): \ \ … --- ## [Compile-time dispatch based on 'type'](https://racket.discourse.group/t/compile-time-dispatch-based-on-type/3405)
**Author:** [@Laurent.O](https://racket.discourse.group/u/Laurent.O)\ **Replies:** 8\ **Last updated:** [December 9, 2024, 8:29pm UTC](https://racket.discourse.group/t/compile-time-dispatch-based-on-type/3405 "2024-12-09T20:29:46Z")
I'm trying to move a runtime dispatch to compile time for efficiency reasons. In the runtime version, I have two 'types', A and B, and a procedure ref-proc that behaves differently depending on the 'type': #lang racket… --- ## [Typed macros in typed racket?](https://racket.discourse.group/t/typed-macros-in-typed-racket/3403)
**Author:** [@Greg\_Davidson](https://racket.discourse.group/u/Greg_Davidson)\ **Replies:** 1\ **Last updated:** [December 9, 2024, 5:33pm UTC](https://racket.discourse.group/t/typed-macros-in-typed-racket/3403 "2024-12-09T17:33:53Z")
Has anyone done any work in having macros which match on the type signature of a form in TypedRacket? --- ## [Evil C constructs](https://racket.discourse.group/t/evil-c-constructs/3402)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 1\ **Last updated:** [December 8, 2024, 5:27pm UTC](https://racket.discourse.group/t/evil-c-constructs/3402 "2024-12-08T17:27:28Z")
Many years ago I saw a conversation on Usenet about the so called evil C constructs like, for example, a while loop inside a switch statement. I’m interested in learning more about them. Does somebody know something? M… --- ## [Advent 2024: Day 4 (In Praise of LACI)](https://racket.discourse.group/t/advent-2024-day-4-in-praise-of-laci/3401)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 0\ **Last updated:** [December 7, 2024, 7:18pm UTC](https://racket.discourse.group/t/advent-2024-day-4-in-praise-of-laci/3401 "2024-12-07T19:18:02Z")
Ouch! A bit late. Here's my "day 4" post on Prabakhar Ragde's "Logic and Computation Intertwined": Merry christmas to all! --- ## [Converting Struct to JSON](https://racket.discourse.group/t/converting-struct-to-json/3399)
**Author:** [@BenRaz123](https://racket.discourse.group/u/BenRaz123)\ **Replies:** 2\ **Last updated:** [December 6, 2024, 7:09pm UTC](https://racket.discourse.group/t/converting-struct-to-json/3399 "2024-12-06T19:09:01Z")
Hello, and thanks for answering my beginner question! If I have this struct in typed racket: #lang typed/racket (struct Person (\[name : String\] \[age : Number\] \[gender : Boolean\])) What's the easiest method of converti… --- ## [Advent 2024: Day 5 (Epicycles Revisited)](https://racket.discourse.group/t/advent-2024-day-5-epicycles-revisited/3395)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 1\ **Last updated:** [December 5, 2024, 4:38pm UTC](https://racket.discourse.group/t/advent-2024-day-5-epicycles-revisited/3395 "2024-12-05T16:38:12Z")
Hi, Racket Discourse. Just a quick one for today, since I have been swamped with work all of a sudden... I reused some of my ideas from the year to make a snow globe! The first part of the simulation is basically the … --- ## [Best practice calling racket from rash?](https://racket.discourse.group/t/best-practice-calling-racket-from-rash/3346)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 2\ **Last updated:** [December 5, 2024, 3:53pm UTC](https://racket.discourse.group/t/best-practice-calling-racket-from-rash/3346 "2024-12-05T15:53:15Z")
I'm starting to use rash, and having a lot of fun. One question that I have is around best practices when invoking racket code. Specifically, as you might imagine, I have a bunch of shell scripts that invoke racket. When… --- ## [Matching Question](https://racket.discourse.group/t/matching-question/3391)
**Author:** [@Rugged](https://racket.discourse.group/u/Rugged)\ **Replies:** 3\ **Last updated:** [December 4, 2024, 1:45pm UTC](https://racket.discourse.group/t/matching-question/3391 "2024-12-04T13:45:24Z")
Hi, I am a bit confused why the following code doesn't produce an output: (match #f \[else (cond \[#f 'not-evaluated\] \[else 'also-not-evaluated\])\]) I would expect it to output 'also-not-evaluated … --- ## [Valid numeric entity refused by xexpr-\>xml](https://racket.discourse.group/t/valid-numeric-entity-refused-by-xexpr-xml/3393)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 2\ **Last updated:** [December 4, 2024, 12:15pm UTC](https://racket.discourse.group/t/valid-numeric-entity-refused-by-xexpr-xml/3393 "2024-12-04T12:15:06Z")
hello, i'm facing this strange error : xexpr-\>xml: contract violation; Not an Xexpr. Expected a string, symbol, valid numeric entity, comment, processing instruction, or list, given 2.2384341637010676 Context: '(DATA… --- ## [Creating a colorful HD wallpaper using Racket](https://racket.discourse.group/t/creating-a-colorful-hd-wallpaper-using-racket/3389)
**Author:** [@JustinZed](https://racket.discourse.group/u/JustinZed)\ **Replies:** 4\ **Last updated:** [December 3, 2024, 5:09pm UTC](https://racket.discourse.group/t/creating-a-colorful-hd-wallpaper-using-racket/3389 "2024-12-03T17:09:30Z")
For today's Advent Calendar, I'm sharing a colorful wallpaper I made for my phone using Racket. There's nothing too deep about it, just a bit of fun, but it does demonstrate a simple way to create a nice rainbow color gr… --- ## [Category Theory in Programming](https://racket.discourse.group/t/category-theory-in-programming/3375)
**Author:** [@NoahStoryM](https://racket.discourse.group/u/NoahStoryM)\ **Replies:** 3\ **Last updated:** [December 3, 2024, 2:47am UTC](https://racket.discourse.group/t/category-theory-in-programming/3375 "2024-12-03T02:47:15Z")
The full tutorial is here CTP. In this tutorial, I explore the applications of category theory in programming, using Racket to represent abstract mathematical concepts. The completed sections introduce categories, funct… --- ## [Expr/c and wrap-expr/c not error highlighting what contract states it is blaming](https://racket.discourse.group/t/expr-c-and-wrap-expr-c-not-error-highlighting-what-contract-states-it-is-blaming/3369)
**Author:** [@sora22](https://racket.discourse.group/u/sora22)\ **Replies:** 13\ **Last updated:** [December 2, 2024, 7:29pm UTC](https://racket.discourse.group/t/expr-c-and-wrap-expr-c-not-error-highlighting-what-contract-states-it-is-blaming/3369 "2024-12-02T19:29:43Z")
Don't know if I'm doing something incorrect or if this is just a bug. Been having a nightmare of a time trying to get expr/c and wrap-expr/c to work with the macros I've been writing. Whenever I attempt to use one of the… --- ## [Advent of Code 2024 Leaderboard](https://racket.discourse.group/t/advent-of-code-2024-leaderboard/3374)
**Author:** [@SamPhillips](https://racket.discourse.group/u/SamPhillips)\ **Replies:** 5\ **Last updated:** [December 2, 2024, 4:22pm UTC](https://racket.discourse.group/t/advent-of-code-2024-leaderboard/3374 "2024-12-02T16:22:10Z")
It's time again for the Advent of Code. The puzzles will start at midnight (UTC-5) on December 1, 2024. Once again, we will have the Racket leaderboard. Use the join code 22197-a7a01707 to be included. Any language in t… --- ## [Scraping XML sitemaps with Racket](https://racket.discourse.group/t/scraping-xml-sitemaps-with-racket/3386)
**Author:** [@benknoble](https://racket.discourse.group/u/benknoble)\ **Replies:** 0\ **Last updated:** [December 2, 2024, 3:55pm UTC](https://racket.discourse.group/t/scraping-xml-sitemaps-with-racket/3386 "2024-12-02T15:55:01Z")
Advent of Racket, Day 2! The full post describes the "memex" method and a short Racket program to help me review old blog posts. Enjoy! --- ## [Fxvector-\>cpointer?](https://racket.discourse.group/t/fxvector-cpointer/3385)
**Author:** [@Laurent.O](https://racket.discourse.group/u/Laurent.O)\ **Replies:** 1\ **Last updated:** [December 2, 2024, 1:48pm UTC](https://racket.discourse.group/t/fxvector-cpointer/3385 "2024-12-02T13:48:33Z")
Would it be possible for Racket to export something like fxvector-\>cpointer? Racket has flvector-\>cpointer, which allows me to make my own my-shared-flector struct work also for flvector without losing any efficiency (a… --- ## [Format for multimedia files?](https://racket.discourse.group/t/format-for-multimedia-files/3365)
**Author:** [@ToddOBryan](https://racket.discourse.group/u/ToddOBryan)\ **Replies:** 4\ **Last updated:** [December 1, 2024, 2:55pm UTC](https://racket.discourse.group/t/format-for-multimedia-files/3365 "2024-12-01T14:55:37Z")
Where is the description of what the format for multimedia files is? A lot of my early assignments include images and I'd like to be able to look at student text inside the files for analysis and grading. --- ## [FFI: 'file' size of a non-file file descriptor](https://racket.discourse.group/t/ffi-file-size-of-a-non-file-file-descriptor/3341)
**Author:** [@Laurent.O](https://racket.discourse.group/u/Laurent.O)\ **Replies:** 8\ **Last updated:** [November 29, 2024, 5:31pm UTC](https://racket.discourse.group/t/ffi-file-size-of-a-non-file-file-descriptor/3341 "2024-11-29T17:31:44Z")
I'm currently playing with shared memory spaces via the FFI, looking into shm\_open and mmap. After obtaining a file descriptor fd corresponding to an existing such space, I want to find out the underlying 'file' size. H… --- ## [Interactive Fiction?](https://racket.discourse.group/t/interactive-fiction/3304)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 14\ **Last updated:** [November 29, 2024, 1:23pm UTC](https://racket.discourse.group/t/interactive-fiction/3304 "2024-11-29T13:23:41Z")
Hi, Racket Discourse. I have been playing around with bags (or multisets) for a while now, and thinking of ways to employ them, I have time and again come back to interactive fiction. There is this really neat project,… --- ## [A new way to type mutable data structures with opposite variance in typed racket](https://racket.discourse.group/t/a-new-way-to-type-mutable-data-structures-with-opposite-variance-in-typed-racket/1846)
**Author:** [@NoahStoryM](https://racket.discourse.group/u/NoahStoryM)\ **Replies:** 16\ **Last updated:** [November 29, 2024, 2:03am UTC](https://racket.discourse.group/t/a-new-way-to-type-mutable-data-structures-with-opposite-variance-in-typed-racket/1846 "2024-11-29T02:03:52Z")
Hi everyone, I have been experimenting with a way to define types with opposite variance in typed racket (see also Is it possible to make Mutable Types support subtype? · racket/typed-racket · Discussion #1129 · GitHub)… --- ## [Visualising programs and program transformations](https://racket.discourse.group/t/visualising-programs-and-program-transformations/3361)
**Author:** [@aanastasiou](https://racket.discourse.group/u/aanastasiou)\ **Replies:** 7\ **Last updated:** [November 29, 2024, 12:06am UTC](https://racket.discourse.group/t/visualising-programs-and-program-transformations/3361 "2024-11-29T00:06:17Z")
Hello Are there any existing tools that can take racket code and visualise it as the tree it is? I would like to visualise program transformations effected by macros. So, for example, given: (define a (+ 5 6)) The gr… --- ## [Enhanced infix syntax in new version of Scheme+](https://racket.discourse.group/t/enhanced-infix-syntax-in-new-version-of-scheme/3358)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 1\ **Last updated:** [November 28, 2024, 10:35pm UTC](https://racket.discourse.group/t/enhanced-infix-syntax-in-new-version-of-scheme/3358 "2024-11-28T22:35:14Z")
Hello, I present a new version of Scheme+ that allow better infix notation. For Racket R6RS for now (A Racket version will be soon available also) it requires also a new version of SRFI-105 curly-infix reader and pars… --- ## [Nonprogrammer zine](https://racket.discourse.group/t/nonprogrammer-zine/3355)
**Author:** [@qeef](https://racket.discourse.group/u/qeef)\ **Replies:** 7\ **Last updated:** [November 28, 2024, 2:31pm UTC](https://racket.discourse.group/t/nonprogrammer-zine/3355 "2024-11-28T14:31:59Z")
Hi. I made my first zine, then translated it into English. It's for nonprogrammers who care to learn what programming is, so I am not sure this is right place to share. However, the approach uses Racket (or Scheme) to… --- ## [Why are struct constructors accessed through a parameter 10-20% faster than using the constructor directly?](https://racket.discourse.group/t/why-are-struct-constructors-accessed-through-a-parameter-10-20-faster-than-using-the-constructor-directly/3364)
**Author:** [@780nm](https://racket.discourse.group/u/780nm)\ **Replies:** 7\ **Last updated:** [November 28, 2024, 12:32am UTC](https://racket.discourse.group/t/why-are-struct-constructors-accessed-through-a-parameter-10-20-faster-than-using-the-constructor-directly/3364 "2024-11-28T00:32:05Z")
Hi! I was looking at the performance impacts of parameters for use in a language project and ran into some odd performance characteristics: accessing struct constructors through a parameterize-introduced binding appears… [Previous page](https://racket.discourse.group/latest.md?page=19) [Next page](https://racket.discourse.group/latest.md?page=21)