# Latest **URL:** https://racket.discourse.group/latest.md?page=9 [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) **Page:** 10 --- ## [How to implement parallel-or?](https://racket.discourse.group/t/how-to-implement-parallel-or/3987)
**Author:** [@ohqo](https://racket.discourse.group/u/ohqo)\ **Replies:** 3\ **Last updated:** [October 27, 2025, 11:42pm UTC](https://racket.discourse.group/t/how-to-implement-parallel-or/3987 "2025-10-27T23:42:20Z")
The parallel-or operation allows you to run two computations in parallel and either immediately returns true if one of the computations halts with true or returns false if both computations halt with false. I couldn't f… --- ## [FFI Callback stdio](https://racket.discourse.group/t/ffi-callback-stdio/3984)
**Author:** [@ThePuzzlemaker](https://racket.discourse.group/u/ThePuzzlemaker)\ **Replies:** 1\ **Last updated:** [October 27, 2025, 12:14pm UTC](https://racket.discourse.group/t/ffi-callback-stdio/3984 "2025-10-27T12:14:12Z")
How can I do I/O to stdin/out/err in an FFI callback? Is it simply impossible (as the docs would lead me to believe, at least for the CS backend)? I don't care about if anything on the current OS thread blocks during th… --- ## [The end of BC downloads?](https://racket.discourse.group/t/the-end-of-bc-downloads/3734)
**Author:** [@mflatt](https://racket.discourse.group/u/mflatt)\ **Replies:** 8\ **Last updated:** [October 26, 2025, 6:06pm UTC](https://racket.discourse.group/t/the-end-of-bc-downloads/3734 "2025-10-26T18:06:51Z")
We're overhauling the Racket installer builds for the main download site (after the upcoming v8.17) and snapshot sites (sooner). One question is how much to keep building installers for the old BC variant of Racket. The … --- ## [Call for Papers: Symposium on Functional and Logic Programming (May 26-28, Akita, Japan)](https://racket.discourse.group/t/call-for-papers-symposium-on-functional-and-logic-programming-may-26-28-akita-japan/3921)
**Author:** [@mike](https://racket.discourse.group/u/mike)\ **Replies:** 1\ **Last updated:** [October 26, 2025, 12:41pm UTC](https://racket.discourse.group/t/call-for-papers-symposium-on-functional-and-logic-programming-may-26-28-akita-japan/3921 "2025-10-26T12:41:49Z")
18th International Symposium on Functional and Logic Programming May 26-28, 2026, Akita, Japan FLOPS aims to bring together practitioners, researchers and implementers of declarative programming, to discuss mutually int… --- ## [How Cloudflare Uses Racket and Rosette to Verify DNS Changes](https://racket.discourse.group/t/how-cloudflare-uses-racket-and-rosette-to-verify-dns-changes/3983)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [October 25, 2025, 9:05pm UTC](https://racket.discourse.group/t/how-cloudflare-uses-racket-and-rosette-to-verify-dns-changes/3983 "2025-10-25T21:05:57Z")
How Cloudflare Uses Racket and Rosette to Verify DNS Changes Keynote presentation by James Larisch and Suleman Ahmad at (fifteenth RacketCon) October 4-5, 2025 UMass Boston https://youtu.be/7Twlh-Opq5E (M… --- ## [How to use subprocess](https://racket.discourse.group/t/how-to-use-subprocess/3982)
**Author:** [@AndreMayers](https://racket.discourse.group/u/AndreMayers)\ **Replies:** 4\ **Last updated:** [October 25, 2025, 5:48pm UTC](https://racket.discourse.group/t/how-to-use-subprocess/3982 "2025-10-25T17:48:37Z")
In the following code, st-out is always #f. Why? I tried several variants of the following code. (set st-in (open the output file "out-file.txt")) (set st-out (open input file "in-file.txt" )) (define-values (newp… --- ## [Help test via snapshots: parallel threads](https://racket.discourse.group/t/help-test-via-snapshots-parallel-threads/3920)
**Author:** [@mflatt](https://racket.discourse.group/u/mflatt)\ **Replies:** 24\ **Last updated:** [October 25, 2025, 12:19pm UTC](https://racket.discourse.group/t/help-test-via-snapshots-parallel-threads/3920 "2025-10-25T12:19:28Z")
We expect that the next Racket release (tentatively v9.0) will have additional support for parallelism. We need your help to get it right. Racket has always provided lightweight threads for concurrency, but Racket threa… --- ## [Gathering macro-time information](https://racket.discourse.group/t/gathering-macro-time-information/3981)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 2\ **Last updated:** [October 25, 2025, 3:58am UTC](https://racket.discourse.group/t/gathering-macro-time-information/3981 "2025-10-25T03:58:26Z")
Context: Now I am implementing in Racket a few of the control structures of Ink, a notation for writing text adventure games. (If you are interested, see Writing web-based interactive fiction with ink ) I have the fol… --- ## [Providing new forms to shplait](https://racket.discourse.group/t/providing-new-forms-to-shplait/3978)
**Author:** [@kimmyg](https://racket.discourse.group/u/kimmyg)\ **Replies:** 1\ **Last updated:** [October 22, 2025, 4:31pm UTC](https://racket.discourse.group/t/providing-new-forms-to-shplait/3978 "2025-10-22T16:31:51Z")
I would like a single module to provide both a new datatype and new expression form to importing shplait modules. The expression form is defined as a macro but AFAICT isn’t expressible using shplait’s restricted macros. … --- ## [An Array Language](https://racket.discourse.group/t/an-array-language/3980)
**Author:** [@ulambda](https://racket.discourse.group/u/ulambda)\ **Replies:** 0\ **Last updated:** [October 21, 2025, 8:50pm UTC](https://racket.discourse.group/t/an-array-language/3980 "2025-10-21T20:50:25Z")
miscellaneous/array0.rkt at main · alpha-beta-eta/miscellaneous Basically, I follow the idea in the link below: Image Processing Playground with Array Languages (faithfully) translate the OCaml code into Racket and ma… --- ## [Arrays proposal: Help to write idiomatic typed math/array example](https://racket.discourse.group/t/arrays-proposal-help-to-write-idiomatic-typed-math-array-example/3972)
**Author:** [@Gambiteer](https://racket.discourse.group/u/Gambiteer)\ **Replies:** 6\ **Last updated:** [October 21, 2025, 8:47pm UTC](https://racket.discourse.group/t/arrays-proposal-help-to-write-idiomatic-typed-math-array-example/3972 "2025-10-21T20:47:46Z")
Racket's math/array is a very large library. I'm trying to refine/expand SRFI 231 to a library that is smaller than math/array but with sufficient performance and expressiveness. Examples using array libraries in many … --- ## [TIL how to convert hex triplet to \`racket/draw\` color](https://racket.discourse.group/t/til-how-to-convert-hex-triplet-to-racket-draw-color/3979)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [October 21, 2025, 1:11pm UTC](https://racket.discourse.group/t/til-how-to-convert-hex-triplet-to-racket-draw-color/3979 "2025-10-21T13:11:45Z")
TIL how to convert a hex triplet to racket/draw color ;; Convert hex triplet to \`racket/draw\` color ;; hex-triplet-\>color% : hex -\> colour% (define (hex-triplet-\>color% x) (define-values \[r g b\] (values (arithmeti… --- ## [Execute thrice only](https://racket.discourse.group/t/execute-thrice-only/3974)
**Author:** [@hendrikboom3](https://racket.discourse.group/u/hendrikboom3)\ **Replies:** 4\ **Last updated:** [October 19, 2025, 12:55am UTC](https://racket.discourse.group/t/execute-thrice-only/3974 "2025-10-19T00:55:27Z")
Let's say I want a particular piece of code to execute at most three times within the execution of a larger program. The obvious code is something like (define globalcounter 3) and where I have the piece of code I wra… --- ## [CS Pictionary!](https://racket.discourse.group/t/cs-pictionary/3975)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [October 18, 2025, 12:39pm UTC](https://racket.discourse.group/t/cs-pictionary/3975 "2025-10-18T12:39:42Z")
A bit of fun happened at the Qi meeting yesterday that can’t wait for the next Qi meeting notes CS Pictionary! What started as a Python script became a Racket version thanks to @SamPhillips and eventually a R16 comm… --- ## [Racket v9.0 branching is done!](https://racket.discourse.group/t/racket-v9-0-branching-is-done/3973)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 0\ **Last updated:** [October 17, 2025, 6:38am UTC](https://racket.discourse.group/t/racket-v9-0-branching-is-done/3973 "2025-10-17T06:38:18Z")
The release process for v9.0 has begun: release checkpoints have been created for all packages in the main distribution, and release branches have been created when necessary. You can go on using \`master\` branches as usu… --- ## [Providing name only to sub-module?](https://racket.discourse.group/t/providing-name-only-to-sub-module/3918)
**Author:** [@pcn](https://racket.discourse.group/u/pcn)\ **Replies:** 11\ **Last updated:** [October 12, 2025, 12:06am UTC](https://racket.discourse.group/t/providing-name-only-to-sub-module/3918 "2025-10-12T00:06:45Z")
Context: Inspired by Lean's #guard commands, I'd like to implement "static unit tests" in Racket, where tests give the same interactive feedback as types. An example would look something like below: (define (factorial … --- ## [Racket v9.0 release has started](https://racket.discourse.group/t/racket-v9-0-release-has-started/3967)
**Author:** [@jbclements](https://racket.discourse.group/u/jbclements)\ **Replies:** 0\ **Last updated:** [October 11, 2025, 10:28am UTC](https://racket.discourse.group/t/racket-v9-0-release-has-started/3967 "2025-10-11T10:28:33Z")
The release process for v9.0 will begin in about a week. If you have any new features that you want in and are relatively close to to being done, now is a good time to do that. Upcoming dates: - 16th: Branch day, merg… --- ## [Return from a lambda](https://racket.discourse.group/t/return-from-a-lambda/3960)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 11\ **Last updated:** [October 8, 2025, 8:46am UTC](https://racket.discourse.group/t/return-from-a-lambda/3960 "2025-10-08T08:46:19Z")
Hi, i have some functions def that allow returning early from function defined. But i have a few difficulties to pass from the version 'define to the version 'lambda. 'def is defined this way (code shortened): (modul… --- ## [Arrays proposal: New minimal implementation](https://racket.discourse.group/t/arrays-proposal-new-minimal-implementation/3965)
**Author:** [@Gambiteer](https://racket.discourse.group/u/Gambiteer)\ **Replies:** 0\ **Last updated:** [October 7, 2025, 2:19am UTC](https://racket.discourse.group/t/arrays-proposal-new-minimal-implementation/3965 "2025-10-07T02:19:57Z")
At this branch: I've now committed a "minimal" implementation with no specialized code or error checking, and a test program that can be used to test both the small and regular implementations. The stripped-down rout… --- ## [RacketCon 2025 follow-up](https://racket.discourse.group/t/racketcon-2025-follow-up/3964)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [October 6, 2025, 10:45am UTC](https://racket.discourse.group/t/racketcon-2025-follow-up/3964 "2025-10-06T10:45:19Z")
Hope everyone had a great RacketCon. Many thanks to the presenters, participants in-person and remote, the organisers and UMass Boston for hosting us. Please send feedback to the team at con-organizers@racket-lang.org … --- ## [Racket meet-up - RacketCon party 🎉 - Saturday, 4 October 2025 at 17:00 UTC](https://racket.discourse.group/t/racket-meet-up-racketcon-party-saturday-4-october-2025-at-17-00-utc/3963)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 3\ **Last updated:** [October 4, 2025, 9:53am UTC](https://racket.discourse.group/t/racket-meet-up-racketcon-party-saturday-4-october-2025-at-17-00-utc/3963 "2025-10-04T09:53:40Z")
Everyone is welcome to join us for the :racket: Racket meet-up RacketCon party🎉: Saturday, 4 October 2025 at 17:00 UTC. Update: We have moved the meet-up 1 hour earlier so we don't clash with presentations. I’m still … --- ## [RacketCon chat channel](https://racket.discourse.group/t/racketcon-chat-channel/3962)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [October 3, 2025, 10:59am UTC](https://racket.discourse.group/t/racketcon-chat-channel/3962 "2025-10-03T10:59:38Z")
For those attending RacketCon in person or remotely we have a racketcon chat channel on the racket discord at Racket The livestream is free - but the registration page includes an option to register for $10 USD to help … --- ## [How to get the cool v8.18.0.15-2025-09-17-47ef361823 version?](https://racket.discourse.group/t/how-to-get-the-cool-v8-18-0-15-2025-09-17-47ef361823-version/3949)
**Author:** [@shhyou](https://racket.discourse.group/u/shhyou)\ **Replies:** 1\ **Last updated:** [October 1, 2025, 7:56am UTC](https://racket.discourse.group/t/how-to-get-the-cool-v8-18-0-15-2025-09-17-47ef361823-version/3949 "2025-10-01T07:56:00Z")
Only recently I noticed that building Racket from Git HEAD gave the cool commit-sha version. I suppose this has be added to Racket for a long time, but I still don't get the commit-sha versions when building the git clon… --- ## [Broadcasting, mutability, and non-strict arrays in math/array](https://racket.discourse.group/t/broadcasting-mutability-and-non-strict-arrays-in-math-array/3956)
**Author:** [@Gambiteer](https://racket.discourse.group/u/Gambiteer)\ **Replies:** 3\ **Last updated:** [October 1, 2025, 1:53am UTC](https://racket.discourse.group/t/broadcasting-mutability-and-non-strict-arrays-in-math-array/3956 "2025-10-01T01:53:58Z")
TL;DR version: Applying array broadcasting to mutable or non-strict arrays can be very difficult to reason about, so should one restrict broadcasting to strict, immutable arrays? or ignore the difficulties and learn to … --- ## [What's the idiomatic way of using untyped collections/data structures in typed code?](https://racket.discourse.group/t/whats-the-idiomatic-way-of-using-untyped-collections-data-structures-in-typed-code/3958)
**Author:** [@ohqo](https://racket.discourse.group/u/ohqo)\ **Replies:** 7\ **Last updated:** [September 27, 2025, 5:53pm UTC](https://racket.discourse.group/t/whats-the-idiomatic-way-of-using-untyped-collections-data-structures-in-typed-code/3958 "2025-09-27T17:53:56Z")
The data-lib library has many useful data structures that are missing from the typed racket standard library. Following the documentation on interacting with untyped code, I was able to use the #:opaque type to import th… --- ## [Scheme+ documentation in Scribble Racket format and new release](https://racket.discourse.group/t/scheme-documentation-in-scribble-racket-format-and-new-release/3957)
**Author:** [@damien\_mattei](https://racket.discourse.group/u/damien_mattei)\ **Replies:** 0\ **Last updated:** [September 26, 2025, 9:50am UTC](https://racket.discourse.group/t/scheme-documentation-in-scribble-racket-format-and-new-release/3957 "2025-09-26T09:50:44Z")
Hi, i wrote the documentation of Scheme+ in Scribble, the official Racket format for documentation: https://docs.racket-lang.org/Scheme-PLUS-for-Racket/index.html It contains also many short examples from my codes for… --- ## [Try a quick experiment with Racket 8.14 and macOS Sequoia?](https://racket.discourse.group/t/try-a-quick-experiment-with-racket-8-14-and-macos-sequoia/3177)
**Author:** [@greghendershott](https://racket.discourse.group/u/greghendershott)\ **Replies:** 4\ **Last updated:** [September 25, 2025, 12:40pm UTC](https://racket.discourse.group/t/try-a-quick-experiment-with-racket-8-14-and-macos-sequoia/3177 "2025-09-25T12:40:57Z")
I'm investigating a bug report about Racket Mode's Emacs front end being unable to talk to its Racket back end. But it turns out Emacs isn't a necessary ingredient? It appears there might be an issue with its Racket bac… --- ## [How to Think About Programs the Way Experts Do (UBC TAs)](https://racket.discourse.group/t/how-to-think-about-programs-the-way-experts-do-ubc-tas/3955)
**Author:** [@markshead](https://racket.discourse.group/u/markshead)\ **Replies:** 2\ **Last updated:** [September 24, 2025, 5:33pm UTC](https://racket.discourse.group/t/how-to-think-about-programs-the-way-experts-do-ubc-tas/3955 "2025-09-24T17:33:49Z")
In October, Susan Chung and Matthew Kang have graciously agreed to share some of their experiences as TAs for the Racket-based CPSC110 at the University of British Columbia. If you might be interested, follow the link to… --- ## [Qi Meeting Time Change](https://racket.discourse.group/t/qi-meeting-time-change/3828)
**Author:** [@countvajhula](https://racket.discourse.group/u/countvajhula)\ **Replies:** 3\ **Last updated:** [September 23, 2025, 8:28pm UTC](https://racket.discourse.group/t/qi-meeting-time-change/3828 "2025-09-23T20:28:26Z")
(starting a new thread to use it for all time changes in the future) Hi folks, Please note that there is a time change for the Qi meeting this week, and we will be meeting tomorrow (Thursday instead of Friday), an hour… --- ## [Can typed racket be used to decrease memory usage?](https://racket.discourse.group/t/can-typed-racket-be-used-to-decrease-memory-usage/3946)
**Author:** [@sora22](https://racket.discourse.group/u/sora22)\ **Replies:** 3\ **Last updated:** [September 23, 2025, 3:24pm UTC](https://racket.discourse.group/t/can-typed-racket-be-used-to-decrease-memory-usage/3946 "2025-09-23T15:24:02Z")
I'm trying to reduce the memory usage of a tool I'm helping to develop, and was wondering if typed racket could help me? The example I had in mind was a vector of type (Mutable-Vectorof Byte). Does typed racket only guar… [Previous page](https://racket.discourse.group/latest.md?page=8) [Next page](https://racket.discourse.group/latest.md?page=10)