# Show & Tell **URL:** https://racket.discourse.group/c/show-and-tell/7.md?page=2 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 3 --- ## [DSLs for Safe iOS/watchOS Communication](https://racket.discourse.group/t/dsls-for-safe-ios-watchos-communication/3570)
**Author:** [@bogdan](https://racket.discourse.group/u/bogdan)\ **Replies:** 2\ **Last updated:** [February 19, 2025, 6:22am UTC](https://racket.discourse.group/t/dsls-for-safe-ios-watchos-communication/3570 "2025-02-19T06:22:53Z")
Just sharing a post I wrote today on enhancing a Swift project by leveraging a Racket DSL. https://defn.io/2025/02/16/type-safe-watchos-communication/ --- ## [Working Through Exercises in HtDP 2nd Edition](https://racket.discourse.group/t/working-through-exercises-in-htdp-2nd-edition/3522)
**Author:** [@OldDutchCap](https://racket.discourse.group/u/OldDutchCap)\ **Replies:** 11\ **Last updated:** [February 13, 2025, 9:15pm UTC](https://racket.discourse.group/t/working-through-exercises-in-htdp-2nd-edition/3522 "2025-02-13T21:15:03Z")
Not that I think this is anything particularly noteworthy or special but I've been working through the exercises in HtDP 2nd Edition and posting my answers up to my blog lately. I decided to try to do the exercises with… --- ## [Forthy Friday (Macro)](https://racket.discourse.group/t/forthy-friday-macro/3547)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 1\ **Last updated:** [February 13, 2025, 6:12pm UTC](https://racket.discourse.group/t/forthy-friday-macro/3547 "2025-02-13T18:12:03Z")
Hi, Racket Discourse. I was feeling a bit antsy last night and thought it would be good idea to take a look at forsp, which I'd glanced at before, but forgotten about again in the meantime. Anthony presents a very inte… --- ## [A Little More On Powershell Scripting With Racket](https://racket.discourse.group/t/a-little-more-on-powershell-scripting-with-racket/3525)
**Author:** [@OldDutchCap](https://racket.discourse.group/u/OldDutchCap)\ **Replies:** 5\ **Last updated:** [January 31, 2025, 4:43pm UTC](https://racket.discourse.group/t/a-little-more-on-powershell-scripting-with-racket/3525 "2025-01-31T16:43:21Z")
Just thought others might find this somewhat interesting: https://onor.io/2025/01/more-scripting-with-racket.html --- ## [Racket tutorials](https://racket.discourse.group/t/racket-tutorials/3511)
**Author:** [@Eeb](https://racket.discourse.group/u/Eeb)\ **Replies:** 2\ **Last updated:** [January 26, 2025, 6:40pm UTC](https://racket.discourse.group/t/racket-tutorials/3511 "2025-01-26T18:40:20Z")
Hi everyone! I've recently started creating educational content on YouTube in my free time, and I started a series about everyone’s favorite programming language—Racket! There isn’t much content on racket so I thought it… --- ## [Dealing with multiple values](https://racket.discourse.group/t/dealing-with-multiple-values/3500)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 3\ **Last updated:** [January 19, 2025, 11:20pm UTC](https://racket.discourse.group/t/dealing-with-multiple-values/3500 "2025-01-19T23:20:33Z")
Hello, some months ago, when I started working with streams, I developed a procedure that takes some single valued streams and return a multi valued stream. Then I thought if the opposite was possible: create a procedur… --- ## [3d dataset visualization using the plot package](https://racket.discourse.group/t/3d-dataset-visualization-using-the-plot-package/1563)
**Author:** [@alexh](https://racket.discourse.group/u/alexh)\ **Replies:** 2\ **Last updated:** [January 17, 2025, 11:20am UTC](https://racket.discourse.group/t/3d-dataset-visualization-using-the-plot-package/1563 "2025-01-17T11:20:52Z")
I needed a way to visualize a 3D dataset and I used the racket plot package for it, and, while the dataset is not Racket related, I thought I share the end result here: The racket plot package uses paralle… --- ## [A real code example in infix/prefix Scheme+ for Racket](https://racket.discourse.group/t/a-real-code-example-in-infix-prefix-scheme-for-racket/3491)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [January 14, 2025, 1:05pm UTC](https://racket.discourse.group/t/a-real-code-example-in-infix-prefix-scheme-for-racket/3491 "2025-01-14T13:05:04Z")
Hello and Happy new year, i think interesting to post an example of code with Scheme+ for Racket used in real in a web application. (that also use PHP,Python...) Here the Racket Scheme+ code is only used as a glue betw… --- ## [My Racket page: Project Euler problems 1..50 and a lot of Gamble probabilistic programming models](https://racket.discourse.group/t/my-racket-page-project-euler-problems-1-50-and-a-lot-of-gamble-probabilistic-programming-models/3180)
**Author:** [@hakank](https://racket.discourse.group/u/hakank)\ **Replies:** 6\ **Last updated:** [December 17, 2024, 4:24pm UTC](https://racket.discourse.group/t/my-racket-page-project-euler-problems-1-50-and-a-lot-of-gamble-probabilistic-programming-models/3180 "2024-12-17T16:24:15Z")
(I'm still a little embarrassed about my newbie question earlier, but nowadays I only focus on Racket and don't mix with other Lisps, except for Emacs Lisp occasionally. I still do newbie mistakes, but not very often tha… --- ## [Finite state automaton for parsing](https://racket.discourse.group/t/finite-state-automaton-for-parsing/3421)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [December 15, 2024, 6:19pm UTC](https://racket.discourse.group/t/finite-state-automaton-for-parsing/3421 "2024-12-15T18:19:29Z")
Hi, on this end of week i decided to update a bit my infix parser to allow some expressions as in other language, i take in example Python: Python 3.12.3 (main, Nov 6 2024, 18:32:19) \[GCC 13.2.0\] on linux Type "help",… --- ## [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… --- ## [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 … --- ## [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… --- ## [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)… --- ## [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… --- ## [Equations as s-expression and convert them to LaTeX](https://racket.discourse.group/t/equations-as-s-expression-and-convert-them-to-latex/3343)
**Author:** [@chemPolonium](https://racket.discourse.group/u/chemPolonium)\ **Replies:** 1\ **Last updated:** [November 27, 2024, 10:59pm UTC](https://racket.discourse.group/t/equations-as-s-expression-and-convert-them-to-latex/3343 "2024-11-27T22:59:14Z")
I found that writing LaTeX formulas is a tiring task, requiring the input of many special characters, especially when dealing with structures like matrices and parentheses. Therefore, I tried using S-expressions to descr… --- ## [Stop doing show and tell!](https://racket.discourse.group/t/stop-doing-show-and-tell/3362)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [November 27, 2024, 7:43pm UTC](https://racket.discourse.group/t/stop-doing-show-and-tell/3362 "2024-11-27T19:43:21Z")
Stop doing show and tell…we need Racket Advent Calendar entries S. --- ## [Implementing a 2d point with pairs vs. flvectors vs. structs vs. complex, a primitive benchmark](https://racket.discourse.group/t/implementing-a-2d-point-with-pairs-vs-flvectors-vs-structs-vs-complex-a-primitive-benchmark/3274)
**Author:** [@williewillus](https://racket.discourse.group/u/williewillus)\ **Replies:** 16\ **Last updated:** [November 20, 2024, 2:47am UTC](https://racket.discourse.group/t/implementing-a-2d-point-with-pairs-vs-flvectors-vs-structs-vs-complex-a-primitive-benchmark/3274 "2024-11-20T02:47:57Z")
Recently had a thought experiment since I'm making a 2d game, which is heavy on numerical manipulation of 2d points. \[I'm using Chez Scheme for the game, but that's not too relevant to this post\]. The question was, the… --- ## [Furi-Kuri with Epicycles](https://racket.discourse.group/t/furi-kuri-with-epicycles/3276)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 0\ **Last updated:** [October 29, 2024, 12:07am UTC](https://racket.discourse.group/t/furi-kuri-with-epicycles/3276 "2024-10-29T00:07:59Z")
Hi, Racket Discourse. All the talk about 2D coordinates reminded me I had been playing around with Fourier Transforms earlier in the year. I had always been intrigued by them, but never really taken the time to grok th… --- ## [A Very Simple Trace Viewer/Debugger](https://racket.discourse.group/t/a-very-simple-trace-viewer-debugger/3238)
**Author:** [@alpaylan](https://racket.discourse.group/u/alpaylan)\ **Replies:** 1\ **Last updated:** [October 18, 2024, 1:15pm UTC](https://racket.discourse.group/t/a-very-simple-trace-viewer-debugger/3238 "2024-10-18T13:15:59Z")
I wrote a trace viewer to collapse/traverse the inputs format I get by using trace f for debugging my programs post hoc. I haven't pushed the code into a public repository yet, but it's all self-contained in the HTML pag… --- ## [A match-like DSL for deep immutable updates](https://racket.discourse.group/t/a-match-like-dsl-for-deep-immutable-updates/3220)
**Author:** [@quasarbright](https://racket.discourse.group/u/quasarbright)\ **Replies:** 2\ **Last updated:** [October 12, 2024, 6:24pm UTC](https://racket.discourse.group/t/a-match-like-dsl-for-deep-immutable-updates/3220 "2024-10-12T18:24:21Z")
I made an optics library called "Ocular Patdown" that features a match-like DSL for performing deep immutable updates. Example: \> (update (list 1 2 3) \[(list a b c) (set! a #t) (modify! b -)\]) '(#t -2 … --- ## [Fun with HTTP Requests](https://racket.discourse.group/t/fun-with-http-requests/3224)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 0\ **Last updated:** [October 12, 2024, 6:11pm UTC](https://racket.discourse.group/t/fun-with-http-requests/3224 "2024-10-12T18:11:11Z")
Hi, Racket Discourse. I have been exposed over the past two years to a much wider variety of ways in which to interact with computers. I have mostly favored building frog-like software preceding this period; low to the … --- ## [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… --- ## [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… --- ## [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… --- ## [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… --- ## [New YAML parser](https://racket.discourse.group/t/new-yaml-parser/3159)
**Author:** [@cadence](https://racket.discourse.group/u/cadence)\ **Replies:** 0\ **Last updated:** [September 9, 2024, 9:48am UTC](https://racket.discourse.group/t/new-yaml-parser/3159 "2024-09-09T09:48:28Z")
I wanted to parse some really big YAML files, but found that the existing package was too slow. So I created my own parser called microyaml. It is not spec-compliant because it has some missing features, but all of the m… [Previous page](https://racket.discourse.group/c/show-and-tell/7.md?page=1) [Next page](https://racket.discourse.group/c/show-and-tell/7.md?page=3)