# Latest **URL:** https://racket.discourse.group/latest.md?page=40 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 41 --- ## [Implementing "splicing" syntax](https://racket.discourse.group/t/implementing-splicing-syntax/2300)
**Author:** [@dominik.pantucek](https://racket.discourse.group/u/dominik.pantucek)\ **Replies:** 3\ **Last updated:** [September 11, 2023, 3:52pm UTC](https://racket.discourse.group/t/implementing-splicing-syntax/2300 "2023-09-11T15:52:58Z")
Hello Racketeers, I am working on a flow language (like a poor sibling of Qi) and realized that one of the things that would allow me to write a better structured code is some kind of "splicing" syntax macros. That is m… --- ## [Relative path for require does not works as i expect](https://racket.discourse.group/t/relative-path-for-require-does-not-works-as-i-expect/2299)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 4\ **Last updated:** [September 10, 2023, 9:43pm UTC](https://racket.discourse.group/t/relative-path-for-require-does-not-works-as-i-expect/2299 "2023-09-10T21:43:01Z")
i have a file path1/file.rkt where i have this: (include "../Scheme-PLUS-for-Racket/main/Scheme-PLUS-for-Racket/Scheme+.rkt") in path2/Scheme+.rkt file i a have: (require "overload.scm"). ;; i also tried "./overload.s… --- ## [Macro to Make Identifiers from String Diagram](https://racket.discourse.group/t/macro-to-make-identifiers-from-string-diagram/2296)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 11\ **Last updated:** [September 10, 2023, 3:27pm UTC](https://racket.discourse.group/t/macro-to-make-identifiers-from-string-diagram/2296 "2023-09-10T15:27:29Z")
Hi, Racket Discourse. I am trying to write a macro using some bits of beautiful-racket so that I can provide a string encoding of a diagram and convert the letter names in the diagram to identifiers which are used to de… --- ## [Is there a way to get DrRacket to indent all on save?](https://racket.discourse.group/t/is-there-a-way-to-get-drracket-to-indent-all-on-save/2009)
**Author:** [@madkins23](https://racket.discourse.group/u/madkins23)\ **Replies:** 8\ **Last updated:** [September 10, 2023, 3:25pm UTC](https://racket.discourse.group/t/is-there-a-way-to-get-drracket-to-indent-all-on-save/2009 "2023-09-10T15:25:08Z")
That's about it. I would like formatting to be done automagically when a definition file is saved. I figure it must be possible, but may be require a script or plugin. I can't find a preference or setting that would do … --- ## [Macros expanding to definitions](https://racket.discourse.group/t/macros-expanding-to-definitions/2301)
**Author:** [@soegaard](https://racket.discourse.group/u/soegaard)\ **Replies:** 0\ **Last updated:** [September 10, 2023, 3:23pm UTC](https://racket.discourse.group/t/macros-expanding-to-definitions/2301 "2023-09-10T15:23:30Z")
Macros expanding to definitions This post is about macros that expand into definitions. The examples will use syntax/parse, so all snippets work if they are preceded with: #lang racket (require (for-syntax racket/synt… --- ## [Any way to hook running a quickscript script on events in Dr. Racket?](https://racket.discourse.group/t/any-way-to-hook-running-a-quickscript-script-on-events-in-dr-racket/1887)
**Author:** [@shawnw](https://racket.discourse.group/u/shawnw)\ **Replies:** 5\ **Last updated:** [September 10, 2023, 3:08pm UTC](https://racket.discourse.group/t/any-way-to-hook-running-a-quickscript-script-on-events-in-dr-racket/1887 "2023-09-10T15:08:34Z")
For example, I have a script to remove trailing whitespace from lines; I'd like to have it automatically run before saving a file. --- ## [Racket crashes with "invalid memory reference"](https://racket.discourse.group/t/racket-crashes-with-invalid-memory-reference/2206)
**Author:** [@wurmli](https://racket.discourse.group/u/wurmli)\ **Replies:** 14\ **Last updated:** [September 10, 2023, 1:42pm UTC](https://racket.discourse.group/t/racket-crashes-with-invalid-memory-reference/2206 "2023-09-10T13:42:22Z")
Does somebody know how to revert to expeditor with racket? I had found on Racket Blog to v8.4 how to change from expeditor to readline. The result looks like this: wurmli@cirrus7:~$ racket Welcome to Racket v8.9 \[cs\]. \>… --- ## [Lisp and hash tables](https://racket.discourse.group/t/lisp-and-hash-tables/2295)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 5\ **Last updated:** [September 9, 2023, 12:03pm UTC](https://racket.discourse.group/t/lisp-and-hash-tables/2295 "2023-09-09T12:03:41Z")
Hello, I don't know if this has already been said by anyone else, but: It’s well known that lisp is based on lists, but lists are based on pairs, so lisp is based on pairs, but pairs are actually vectors of length two,… --- ## [How do I rebuild the Racket repository with changes to the Rumble layer?](https://racket.discourse.group/t/how-do-i-rebuild-the-racket-repository-with-changes-to-the-rumble-layer/2297)
**Author:** [@MartianMoorGrove](https://racket.discourse.group/u/MartianMoorGrove)\ **Replies:** 0\ **Last updated:** [September 8, 2023, 6:49pm UTC](https://racket.discourse.group/t/how-do-i-rebuild-the-racket-repository-with-changes-to-the-rumble-layer/2297 "2023-09-08T18:49:04Z")
Running make at the top-level directory isn't enough, and I'm not finding much Rumble-specific guidance in the README files. My change is a potential performance improvement in hash.ss that I'd like to try. --- ## [RacketCon 2023!](https://racket.discourse.group/t/racketcon-2023/2030)
**Author:** [@jesse](https://racket.discourse.group/u/jesse)\ **Replies:** 7\ **Last updated:** [September 8, 2023, 11:47am UTC](https://racket.discourse.group/t/racketcon-2023/2030 "2023-09-08T11:47:57Z")
Get ready, because here comes RacketCon, RacketCon, RacketCon! Saturday & Sunday, Saturday & Sunday, Saturday & Sunday! October, October, October! 28 & 29, 28 & 29, 28 & 29! 2023, 2023, 2023! … --- ## [Using client-side javascript in the Racket webserver?](https://racket.discourse.group/t/using-client-side-javascript-in-the-racket-webserver/2292)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 1\ **Last updated:** [September 6, 2023, 11:15pm UTC](https://racket.discourse.group/t/using-client-side-javascript-in-the-racket-webserver/2292 "2023-09-06T23:15:27Z")
I'm using the Racket webserver. I've discovered I have to use javascript on the client side. How do I generate a web page that contains javascript? I'm not asking how to write javascript. I've done that before. I'm … --- ## [Trouble with net/cookies](https://racket.discourse.group/t/trouble-with-net-cookies/2278)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 2\ **Last updated:** [September 6, 2023, 10:39pm UTC](https://racket.discourse.group/t/trouble-with-net-cookies/2278 "2023-09-06T22:39:11Z")
I seem to be unable to use the net/cookies package together with the web-server/servlet. With (require web-server/servlet web-server/servlet-env) (require net/cookies) I am told module: identifier already r… --- ## [Why is this \`unsafe-set-car!\` so much slower than \`unsafe-set-immutable-car!\`?](https://racket.discourse.group/t/why-is-this-unsafe-set-car-so-much-slower-than-unsafe-set-immutable-car/2282)
**Author:** [@MartianMoorGrove](https://racket.discourse.group/u/MartianMoorGrove)\ **Replies:** 2\ **Last updated:** [September 5, 2023, 7:27pm UTC](https://racket.discourse.group/t/why-is-this-unsafe-set-car-so-much-slower-than-unsafe-set-immutable-car/2282 "2023-09-05T19:27:56Z")
Here in Racket v8.10 CS I have implemented unsafe-set-car! in a way that is equivalent (I think) to unsafe-set-immutable-car! which is provided by racket/unsafe/ops: #lang racket/base (module prim racket/base (requi… --- ## [Traits and interfaces](https://racket.discourse.group/t/traits-and-interfaces/2267)
**Author:** [@matteo-daddio](https://racket.discourse.group/u/matteo-daddio)\ **Replies:** 1\ **Last updated:** [September 5, 2023, 4:19pm UTC](https://racket.discourse.group/t/traits-and-interfaces/2267 "2023-09-05T16:19:50Z")
Hello, I’m tying to work with traits and I discovered that traits can’t implement interfaces, so I can’t use the is-a? predicate. There’s a solution to this problem: create an empty mixin that adds only the interface d… --- ## [RSVG Package: Missing librsvg-2-2.dll](https://racket.discourse.group/t/rsvg-package-missing-librsvg-2-2-dll/2285)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 2\ **Last updated:** [September 4, 2023, 3:03pm UTC](https://racket.discourse.group/t/rsvg-package-missing-librsvg-2-2-dll/2285 "2023-09-04T15:03:59Z")
Hi, Racket Discourse. I am trying to import .svg files to use in concert with the metapict library. I want to make use of the rsvg package to import the pertinent files, but I receive the following error: ..\\..\\..\\..\\… --- ## [Running racket/gui at 60fps](https://racket.discourse.group/t/running-racket-gui-at-60fps/2276)
**Author:** [@PastAghast](https://racket.discourse.group/u/PastAghast)\ **Replies:** 6\ **Last updated:** [September 3, 2023, 6:13pm UTC](https://racket.discourse.group/t/running-racket-gui-at-60fps/2276 "2023-09-03T18:13:15Z")
I'm working on my first project in Racket. I think it's awesome that the language includes a cross platform GUI toolkit, and I'l like to wrap my head around how to make it perform well. I tried making a small canvas tha… --- ## [How to flush-output through make-output-port?](https://racket.discourse.group/t/how-to-flush-output-through-make-output-port/2280)
**Author:** [@Kalimehtar](https://racket.discourse.group/u/Kalimehtar)\ **Replies:** 1\ **Last updated:** [September 3, 2023, 3:16pm UTC](https://racket.discourse.group/t/how-to-flush-output-through-make-output-port/2280 "2023-09-03T15:16:48Z")
I have made a wrapper around some port via (define my-port (make-output-port 'my-port ; This port is ready when the original is ready: inner-port ; Writing procedure: (lambda (s start end non-bl… --- ## [Equality of namespaces](https://racket.discourse.group/t/equality-of-namespaces/2279)
**Author:** [@joskoot](https://racket.discourse.group/u/joskoot)\ **Replies:** 0\ **Last updated:** [September 2, 2023, 7:13pm UTC](https://racket.discourse.group/t/equality-of-namespaces/2279 "2023-09-02T19:13:39Z")
\#lang racket/base (eq? (make-base-namespace) (make-base-namespace)) ; --\> #f ; ok, understandable. ; Nevertheless: (let ((ns1 (make-base-namespace)) (ns2 (make-base-namespace))) (for/and ((x (in-list (namespace-mapp… --- ## [How to set focus to the only button?](https://racket.discourse.group/t/how-to-set-focus-to-the-only-button/2270)
**Author:** [@Vadim\_Y](https://racket.discourse.group/u/Vadim_Y)\ **Replies:** 5\ **Last updated:** [September 2, 2023, 2:22pm UTC](https://racket.discourse.group/t/how-to-set-focus-to-the-only-button/2270 "2023-09-02T14:22:07Z")
Hello! How to set focus to the only button in the application when it starts? --- ## [What is \`raco demod\` for?](https://racket.discourse.group/t/what-is-raco-demod-for/2272)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [September 1, 2023, 5:07pm UTC](https://racket.discourse.group/t/what-is-raco-demod-for/2272 "2023-09-01T17:07:32Z")
What is raco demod for? and why would you want to demodularize your programs? I'm guessing it makes the resulting code smaller or faster?, but I also want to know what the trade-off is? What do you lose when you demodul… --- ## [Calling into a Chez Scheme library from Racket -- imported symbol rewritten in vm-eval?](https://racket.discourse.group/t/calling-into-a-chez-scheme-library-from-racket-imported-symbol-rewritten-in-vm-eval/2257)
**Author:** [@awwx](https://racket.discourse.group/u/awwx)\ **Replies:** 9\ **Last updated:** [September 1, 2023, 2:15am UTC](https://racket.discourse.group/t/calling-into-a-chez-scheme-library-from-racket-imported-symbol-rewritten-in-vm-eval/2257 "2023-09-01T02:15:31Z")
I have a Chez Scheme library "foo.ss" that I'd like to call from Racket: (library (foo) (export bar) (import (rnrs)) (define (bar) "hello")) From Chez Scheme: $ chezscheme Chez Scheme Version 9.5.4 Copyright… --- ## [Question about macro order expansion](https://racket.discourse.group/t/question-about-macro-order-expansion/2259)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 4\ **Last updated:** [August 30, 2023, 7:49pm UTC](https://racket.discourse.group/t/question-about-macro-order-expansion/2259 "2023-08-30T19:49:37Z")
i have this macro i just modified: ;; "abcdefgh" ;; \> {s\[2 \* 3 - 4 $ 2 \* 3 + 1 $ 2 \* 4 - 6\] \<- "0000"} ;; "ab0d0f0h" ;; $bracket-apply$ is from SRFI 105 bracket-apply is an argument of the macro (define-syntax \<- … --- ## [Do we have a RFC \*process\* for the core Racket language(s)? Do we need one?](https://racket.discourse.group/t/do-we-have-a-rfc-process-for-the-core-racket-language-s-do-we-need-one/2233)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 5\ **Last updated:** [August 30, 2023, 7:45am UTC](https://racket.discourse.group/t/do-we-have-a-rfc-process-for-the-core-racket-language-s-do-we-need-one/2233 "2023-08-30T07:45:36Z")
Do we have a community-led RFC process for the core Racket language(s)? Do we need one? I'll give an example where a community-led RFC process may be valuable: I've noticed the issue below has bitten another experienc… --- ## [By default read-line leaves the \\r character at the end of a line entered on the command line on Windows](https://racket.discourse.group/t/by-default-read-line-leaves-the-r-character-at-the-end-of-a-line-entered-on-the-command-line-on-windows/2235)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 3\ **Last updated:** [August 30, 2023, 5:14am UTC](https://racket.discourse.group/t/by-default-read-line-leaves-the-r-character-at-the-end-of-a-line-entered-on-the-command-line-on-windows/2235 "2023-08-30T05:14:41Z")
Topic for discussion of by default read-line leaves the \\r character at the end of a line entered on the command line on Windows Related GitHub items https://github.com/racket/racket/pull/4074#issuecomment-16858618… --- ## [Windows 10 Aspell Not Responding from DrRacket](https://racket.discourse.group/t/windows-10-aspell-not-responding-from-drracket/2255)
**Author:** [@bakgatviooldoos](https://racket.discourse.group/u/bakgatviooldoos)\ **Replies:** 0\ **Last updated:** [August 28, 2023, 10:50am UTC](https://racket.discourse.group/t/windows-10-aspell-not-responding-from-drracket/2255 "2023-08-28T10:50:10Z")
Hi, Racket Discourse. I am trying to get the spell checker to work in DrRacket on Windows 10 but I keep receiving the following error: The spell program (C:\\msys64\\mingw64\\bin\\aspell.exe) did not respond after 0.1 sec… --- ## [How to run REPL in command-line Racket with another language?](https://racket.discourse.group/t/how-to-run-repl-in-command-line-racket-with-another-language/1848)
**Author:** [@Kalimehtar](https://racket.discourse.group/u/Kalimehtar)\ **Replies:** 7\ **Last updated:** [August 27, 2023, 3:40am UTC](https://racket.discourse.group/t/how-to-run-repl-in-command-line-racket-with-another-language/1848 "2023-08-27T03:40:30Z")
In DrRacket I can simply set #lang basic-demo-3, then in REPL say \> let x = 5 \> print x 5 In command line I tried racket -I basic-demo-3 but it doesn't work. $ racket -I basic-demo-3 Welcome to Racket v8.7 \[cs\]. \> l… --- ## [A Racket library for the Gossip Glomers distributed systems challenges](https://racket.discourse.group/t/a-racket-library-for-the-gossip-glomers-distributed-systems-challenges/2253)
**Author:** [@nikhilm](https://racket.discourse.group/u/nikhilm)\ **Replies:** 0\ **Last updated:** [August 26, 2023, 11:06pm UTC](https://racket.discourse.group/t/a-racket-library-for-the-gossip-glomers-distributed-systems-challenges/2253 "2023-08-26T23:06:36Z")
Gossip Glomers is a series of distributed systems programming challenges from Fly.io. It uses Maelstrom, a platform for describing test workloads that can run your programs as distributed systems nodes. I've been workin… --- ## [My submission for the summer event](https://racket.discourse.group/t/my-submission-for-the-summer-event/2246)
**Author:** [@Antigen-11](https://racket.discourse.group/u/Antigen-11)\ **Replies:** 1\ **Last updated:** [August 26, 2023, 2:46pm UTC](https://racket.discourse.group/t/my-submission-for-the-summer-event/2246 "2023-08-26T14:46:53Z")
Hi I want to participate in this great event whereas I'm not expert in designing racket applications. So I create a simple program here, which is used to view processes' swap usage on Linux. Actually this repository is… --- ## [Fixed size list signatures in htdp/isl+](https://racket.discourse.group/t/fixed-size-list-signatures-in-htdp-isl/2247)
**Author:** [@bremner](https://racket.discourse.group/u/bremner)\ **Replies:** 3\ **Last updated:** [August 26, 2023, 12:57pm UTC](https://racket.discourse.group/t/fixed-size-list-signatures-in-htdp-isl/2247 "2023-08-26T12:57:08Z")
I wanted to try one of the exercises from 6 Functional Abstraction using signatures instead of contracts, but I hit what seems to be a limitation of the signatures in ISL+. In particular there seems to be no way to e… --- ## [How can i use 'map' with a procedure on a list of lists](https://racket.discourse.group/t/how-can-i-use-map-with-a-procedure-on-a-list-of-lists/2251)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 3\ **Last updated:** [August 26, 2023, 12:01pm UTC](https://racket.discourse.group/t/how-can-i-use-map-with-a-procedure-on-a-list-of-lists/2251 "2023-08-26T12:01:56Z")
example : (map + (list 1 2) (list 3 4) (list 5 6)) (9 12) suppose now i have a list : (list (list 1 2) (list 3 4) (list 5 6)) and i want to do the same with the elements of the list, how can i do? note here i have … [Previous page](https://racket.discourse.group/latest.md?page=39) [Next page](https://racket.discourse.group/latest.md?page=41)