# Show & Tell **URL:** https://racket.discourse.group/c/show-and-tell/7.md?page=7 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 8 --- ## [Racket matching or exceeding Golang for Echo server performance](https://racket.discourse.group/t/racket-matching-or-exceeding-golang-for-echo-server-performance/660)
**Author:** [@pseud](https://racket.discourse.group/u/pseud)\ **Replies:** 1\ **Last updated:** [February 9, 2022, 1:53pm UTC](https://racket.discourse.group/t/racket-matching-or-exceeding-golang-for-echo-server-performance/660 "2022-02-09T13:53:10Z")
Hey. It's hard to find many performance comparisons outside of the benchmarks team game, so I thought this might be an interesting data point. I was stumbling around, writing a TCP-based echo server, only later coming a… --- ## [Umask - set default file permissions](https://racket.discourse.group/t/umask-set-default-file-permissions/613)
**Author:** [@winny](https://racket.discourse.group/u/winny)\ **Replies:** 10\ **Last updated:** [February 6, 2022, 6:54pm UTC](https://racket.discourse.group/t/umask-set-default-file-permissions/613 "2022-02-06T18:54:37Z")
Hey all, first post here on discourse :wave: ! I had a use-case to manipulate private, information-sensitive files in Racket, didn't find a way to set the umask so new directories/files have secure permissions (race-con… --- ## [R16 Web App - Community Code Evaluation](https://racket.discourse.group/t/r16-web-app-community-code-evaluation/636)
**Author:** [@Eutro](https://racket.discourse.group/u/Eutro)\ **Replies:** 1\ **Last updated:** [January 30, 2022, 4:54pm UTC](https://racket.discourse.group/t/r16-web-app-community-code-evaluation/636 "2022-01-30T16:54:25Z")
For people that don't know, R16 is originally a Discord bot for interactive, community-driven code evaluation. It saves snippets of code, which can then be recalled and executed on user-provided input. About six months … --- ## [Lang formatted-string](https://racket.discourse.group/t/lang-formatted-string/429)
**Author:** [@dannypsnl](https://racket.discourse.group/u/dannypsnl)\ **Replies:** 1\ **Last updated:** [January 24, 2022, 4:09pm UTC](https://racket.discourse.group/t/lang-formatted-string/429 "2022-01-24T16:09:02Z")
Recently, I made a language that extends racket's string to formatted-string, with it one can write (define-values (a b c) (values 1 2 3)) "a = $a, b = $b, a+b+c = $(+ a b c)" repo: GitHub - dannypsnl/formatted-string:… --- ## [Sketching: Flying Lines](https://racket.discourse.group/t/sketching-flying-lines/580)
**Author:** [@soegaard](https://racket.discourse.group/u/soegaard)\ **Replies:** 4\ **Last updated:** [January 17, 2022, 7:47am UTC](https://racket.discourse.group/t/sketching-flying-lines/580 "2022-01-17T07:47:23Z")
\#lang sketching ; Line segments with start and end points on a Lissajous curve. (define fr 30) ; frame rate (define A 1) (define B 1) (define a 3.) ; experiment with different (define b 2.) ; values fo… --- ## [GUI tool tracking state in time to develop the algorithm](https://racket.discourse.group/t/gui-tool-tracking-state-in-time-to-develop-the-algorithm/568)
**Author:** [@dannypsnl](https://racket.discourse.group/u/dannypsnl)\ **Replies:** 0\ **Last updated:** [January 13, 2022, 8:45pm UTC](https://racket.discourse.group/t/gui-tool-tracking-state-in-time-to-develop-the-algorithm/568 "2022-01-13T20:45:41Z")
repo: GitHub - dannypsnl/re-algo demo: re-algo: track local variables - YouTube The idea is to track the internal state when developing complex functions, imagine state for code is unreal, this tool helps you to get in… --- ## [In-out-logged module updated to show results](https://racket.discourse.group/t/in-out-logged-module-updated-to-show-results/563)
**Author:** [@dstorrs](https://racket.discourse.group/u/dstorrs)\ **Replies:** 0\ **Last updated:** [January 12, 2022, 11:00pm UTC](https://racket.discourse.group/t/in-out-logged-module-updated-to-show-results/563 "2022-01-12T23:00:49Z")
A common pattern I encounter when writing code is that I want to know when control enters a function, what it does while it's there, when it exits, and what it returns. I got tired of writing all this manually, so I cre… --- ## [Splitflap library for Atom/RSS feeds — 1.0](https://racket.discourse.group/t/splitflap-library-for-atom-rss-feeds-1-0/548)
**Author:** [@joeld](https://racket.discourse.group/u/joeld)\ **Replies:** 0\ **Last updated:** [January 10, 2022, 9:01pm UTC](https://racket.discourse.group/t/splitflap-library-for-atom-rss-feeds-1-0/548 "2022-01-10T21:01:41Z")
I updated this library from beta/0.9 to 1.0 over the weekend: https://docs.racket-lang.org/splitflap/index.html I incorporated a lot of changes based on feedback from folks in the original Google groups announcement an… --- ## [Typed Racket interface to the generic graph library](https://racket.discourse.group/t/typed-racket-interface-to-the-generic-graph-library/546)
**Author:** [@scolobb](https://racket.discourse.group/u/scolobb)\ **Replies:** 0\ **Last updated:** [January 10, 2022, 5:29pm UTC](https://racket.discourse.group/t/typed-racket-interface-to-the-generic-graph-library/546 "2022-01-10T17:29:01Z")
Hello all, I have just finished an incomplete Typed Racket interface to the generic graph library. It allows using all the basic functions of the library, e.g.: #lang typed/racket (require typed/graph) (define g0 (u… --- ## [TIL: Enforcing contracts with \`contract-out\` from within an embedded test module](https://racket.discourse.group/t/til-enforcing-contracts-with-contract-out-from-within-an-embedded-test-module/525)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 1\ **Last updated:** [January 4, 2022, 10:40pm UTC](https://racket.discourse.group/t/til-enforcing-contracts-with-contract-out-from-within-an-embedded-test-module/525 "2022-01-04T22:40:28Z")
TL;DR :wink: It's possible to enforce and test contracts defined at the module boundary within a test module in the same file. Do this by require'ing (submod "..") in the test module: (module+ test (require ... … --- ## [Automatic Differentiation in Racket](https://racket.discourse.group/t/automatic-differentiation-in-racket/519)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [January 3, 2022, 3:18pm UTC](https://racket.discourse.group/t/automatic-differentiation-in-racket/519 "2022-01-03T15:18:19Z")
Note: I didn’t make either of these but I thought it was worth sharing neither are on the package catalog rackpropagator Exploring Automatic Differentiation in Racket https://www.lambdadays.org/lambdadays2020/oliver-… --- ## [Raco-exe-multitarget](https://racket.discourse.group/t/raco-exe-multitarget/509)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 0\ **Last updated:** [January 1, 2022, 8:28pm UTC](https://racket.discourse.group/t/raco-exe-multitarget/509 "2022-01-01T20:28:10Z")
Following up on a recent topic, I created a package raco-exe-multitarget. The package relies on raco-cross to implement a raco command exe-multitarget to create standalone binaries for multiple platforms in one go. Here… --- ## [Parallelizing the Racket Web Server](https://racket.discourse.group/t/parallelizing-the-racket-web-server/502)
**Author:** [@bogdan](https://racket.discourse.group/u/bogdan)\ **Replies:** 3\ **Last updated:** [January 1, 2022, 3:35pm UTC](https://racket.discourse.group/t/parallelizing-the-racket-web-server/502 "2022-01-01T15:35:14Z")
I wrote a blog post about using places & units to parallelize Racket web apps. Feedback welcome! --- ## [A language and REPL for SRFI 105 "curly infix"](https://racket.discourse.group/t/a-language-and-repl-for-srfi-105-curly-infix/501)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [December 30, 2021, 10:57pm UTC](https://racket.discourse.group/t/a-language-and-repl-for-srfi-105-curly-infix/501 "2021-12-30T22:57:52Z")
Hi, i adapted a #lang and REPL for SRFI 105: https://github.com/damien-mattei/library-FunctProg/blob/master/racket/SRFI-105.rkt a simple example can be found here: https://github.com/damien-mattei/library-FunctProg/b… --- ## [Todo-txt: todo.txt parser and report tool](https://racket.discourse.group/t/todo-txt-todo-txt-parser-and-report-tool/499)
**Author:** [@sschwarzer](https://racket.discourse.group/u/sschwarzer)\ **Replies:** 0\ **Last updated:** [December 30, 2021, 6:34pm UTC](https://racket.discourse.group/t/todo-txt-todo-txt-parser-and-report-tool/499 "2021-12-30T18:34:38Z")
I've written a library and command line tool to process files following the todo.txt format. todo.txt format overview Each line in a todo.txt file is of the form: x (A) 2021-12-30 2021-12-28 Task with a project +my-pro… --- ## [Qi is now "macro extensible"](https://racket.discourse.group/t/qi-is-now-macro-extensible/471)
**Author:** [@countvajhula](https://racket.discourse.group/u/countvajhula)\ **Replies:** 6\ **Last updated:** [December 27, 2021, 10:39pm UTC](https://racket.discourse.group/t/qi-is-now-macro-extensible/471 "2021-12-27T22:39:29Z")
Some time ago I noticed the paper by Ballantyne et. al. re: making your DSL "macro extensible," with the idea to implement it for Qi. The paper was way over my head so I've had it on the backburner to eventually spend mo… --- ## [Advent of Code 2021 Racket leaderboard](https://racket.discourse.group/t/advent-of-code-2021-racket-leaderboard/118)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 5\ **Last updated:** [December 20, 2021, 12:53pm UTC](https://racket.discourse.group/t/advent-of-code-2021-racket-leaderboard/118 "2021-12-20T12:53:11Z")
2021-12-01T05:00:00Z (UTC) The Advent of Code usually attracts quite a few people. https://adventofcode.com/ If you want to join in the Racket leaderboard key is: 22197-a7a01707. https://adventofcode.com/2021/leaderb… --- ## [Typed Racket: the good and the bad](https://racket.discourse.group/t/typed-racket-the-good-and-the-bad/446)
**Author:** [@micahcantor](https://racket.discourse.group/u/micahcantor)\ **Replies:** 2\ **Last updated:** [December 19, 2021, 10:42pm UTC](https://racket.discourse.group/t/typed-racket-the-good-and-the-bad/446 "2021-12-19T22:42:39Z")
Hi all, I wrote about thoughts I had about using Typed Racket to implement Lox from Crafting Interpreters. Here's a link to the post. --- ## [Announcing uni-table - a Unicode text table renderer with ECMA-48 SGR support](https://racket.discourse.group/t/announcing-uni-table-a-unicode-text-table-renderer-with-ecma-48-sgr-support/278)
**Author:** [@dominik.pantucek](https://racket.discourse.group/u/dominik.pantucek)\ **Replies:** 21\ **Last updated:** [December 16, 2021, 9:08am UTC](https://racket.discourse.group/t/announcing-uni-table-a-unicode-text-table-renderer-with-ecma-48-sgr-support/278 "2021-12-16T09:08:06Z")
IT SLICES! IT DICES! It causes a 100,000 light year-diameter quantum explosion! Based on one innocuous remark\[1\] and a Sunday evening package popularity poll results\[2\], I finally decided to put together various bits… --- ## [GitHub workflow template that can be shared](https://racket.discourse.group/t/github-workflow-template-that-can-be-shared/393)
**Author:** [@dannypsnl](https://racket.discourse.group/u/dannypsnl)\ **Replies:** 2\ **Last updated:** [December 8, 2021, 4:24pm UTC](https://racket.discourse.group/t/github-workflow-template-that-can-be-shared/393 "2021-12-08T16:24:57Z")
To get this work, just fork GitHub - dannypsnl/.github to your account, then you should get the thing like the following --- ## [New chapter in "Logic and Computation Intertwined"](https://racket.discourse.group/t/new-chapter-in-logic-and-computation-intertwined/338)
**Author:** [@plragde](https://racket.discourse.group/u/plragde)\ **Replies:** 5\ **Last updated:** [December 3, 2021, 9:54pm UTC](https://racket.discourse.group/t/new-chapter-in-logic-and-computation-intertwined/338 "2021-12-03T21:54:33Z")
This is perhaps tangential, but my flânerie "Logic and Computation Intertwined" uses Racket as its implementation language. Students learn about propositional and predicate logic by using Racket to construct a small proo… --- ## [Pipechain: an alternative library to threading (with a few extras)](https://racket.discourse.group/t/pipechain-an-alternative-library-to-threading-with-a-few-extras/243)
**Author:** [@slaymaker1907](https://racket.discourse.group/u/slaymaker1907)\ **Replies:** 3\ **Last updated:** [November 24, 2021, 6:30pm UTC](https://racket.discourse.group/t/pipechain-an-alternative-library-to-threading-with-a-few-extras/243 "2021-11-24T18:30:49Z")
slaymaker1907/pipechain (github.com) pipechain (racket-lang.org) I loved the idea behind the threading package but I didn't like how it implicitly added the threaded argument to the end (or beginning). It will still tr… --- ## [Qi tutorial and Jay's challenge](https://racket.discourse.group/t/qi-tutorial-and-jays-challenge/162)
**Author:** [@countvajhula](https://racket.discourse.group/u/countvajhula)\ **Replies:** 8\ **Last updated:** [November 23, 2021, 6:42pm UTC](https://racket.discourse.group/t/qi-tutorial-and-jays-challenge/162 "2021-11-23T18:42:45Z")
Hey all, Following up from RacketCon, based on some feedback (esp. from Jesse Alama and William Hatch) I've created a tutorial for Qi that includes lots of illustrative examples. https://docs.racket-lang.org/qi/Tutoria… --- ## [Crafting Interpreters in Typed Racket](https://racket.discourse.group/t/crafting-interpreters-in-typed-racket/235)
**Author:** [@micahcantor](https://racket.discourse.group/u/micahcantor)\ **Replies:** 0\ **Last updated:** [November 23, 2021, 2:04pm UTC](https://racket.discourse.group/t/crafting-interpreters-in-typed-racket/235 "2021-11-23T14:04:40Z")
Hi all, I wrote a short article about a few thoughts on following the book Crafting Interpreters in Typed Racket, and I was asked to post here as well, in case anyone was interested. Here's the link to the blog post. --- ## [New sexp-comment-fade really looks nice](https://racket.discourse.group/t/new-sexp-comment-fade-really-looks-nice/62)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 3\ **Last updated:** [November 22, 2021, 8:08am UTC](https://racket.discourse.group/t/new-sexp-comment-fade-really-looks-nice/62 "2021-11-22T08:08:25Z")
The new "fade" effect for sexps commented out with hash-semicolons looks really nice: FWIW, this is only available in nightly / HEAD, not in 8.3. It should be in 8.4, though! --- ## [DrRacket now has a command palette!](https://racket.discourse.group/t/drracket-now-has-a-command-palette/55)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [November 8, 2021, 10:58pm UTC](https://racket.discourse.group/t/drracket-now-has-a-command-palette/55 "2021-11-08T22:58:13Z")
DrRacket now has a command palette thanks to @Laurent.O It has full access to core functions, and user added scripts. For installation instructions see Quickscript Scripts for DrRacket · racket/racket Wiki · GitHub --- ## [Racket on Twitch!](https://racket.discourse.group/t/racket-on-twitch/92)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 14\ **Last updated:** [November 12, 2021, 10:26am UTC](https://racket.discourse.group/t/racket-on-twitch/92 "2021-11-12T10:26:48Z")
Announced on Racket Discord: "velcrovan — Today at 16:00 I stream live-coding Racket on Twitch at 7pm CST on Thursdays, including tonight! Come hang out if so inclined." https://www.twitch.tv/velcro\_van @joeld [Previous page](https://racket.discourse.group/c/show-and-tell/7.md?page=6)