# Latest **URL:** https://racket.discourse.group/latest.md [Latest](https://racket.discourse.group/latest.md) · [Categories](https://racket.discourse.group/categories.md) · [Tags](https://racket.discourse.group/tags.md) --- ## [Welcome to Racket Discourse](https://racket.discourse.group/t/welcome-to-racket-discourse/2222)
**Author:** [@system](https://racket.discourse.group/u/system)\ **Replies:** 0\ **Last updated:** [August 16, 2023, 7:12pm UTC](https://racket.discourse.group/t/welcome-to-racket-discourse/2222 "2023-08-16T19:12:02Z")
Welcome! This is a friendly and inclusive place to ask questions, show off neat projects, and participate in the life of this fairly awesome family of languages and its ecosystems. :racket: :racketscript: :star\_struck: … --- ## [A Natural Deduction Renderer (?](https://racket.discourse.group/t/a-natural-deduction-renderer/4396)
**Author:** [@ulambda](https://racket.discourse.group/u/ulambda)\ **Replies:** 0\ **Last updated:** [September 21, 2026, 11:23am UTC](https://racket.discourse.group/t/a-natural-deduction-renderer/4396 "2026-09-21T11:23:44Z")
I write a EDSL which checks a proof (in intuitionistic propositional logic) and then generates a corresponding natural deduction. This is based on my SMathML. (define (type-of var env) (cond ((assoc var env) =\> cdr) … --- ## [(sixteenth RacketCon) tickets on sale now](https://racket.discourse.group/t/sixteenth-racketcon-tickets-on-sale-now/4392)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [September 18, 2026, 10:33pm UTC](https://racket.discourse.group/t/sixteenth-racketcon-tickets-on-sale-now/4392 "2026-09-18T22:33:17Z")
(sixteenth RacketCon) tickets on sale now October 3-4, Oakland, Ca https://con.racket-lang.org/ Get your tickets now at https://www.eventbrite.com/e/racketcon-2026-tickets-1997181002140 Professional $120 Patron $150 … --- ## [A Fairly Simple VC Generator for Hoare Logic](https://racket.discourse.group/t/a-fairly-simple-vc-generator-for-hoare-logic/4391)
**Author:** [@ulambda](https://racket.discourse.group/u/ulambda)\ **Replies:** 0\ **Last updated:** [September 18, 2026, 12:16pm UTC](https://racket.discourse.group/t/a-fairly-simple-vc-generator-for-hoare-logic/4391 "2026-09-18T12:16:21Z")
I wrote a fairly simple verification condition generator in less than 30 lines. (define (subst Q E V) (cond ((pair? Q) (cons (subst (car Q) E V) (subst (cdr Q) E V))) ((eq? Q V) E) … --- ## [ALOE = Scheme + Smalltalk + Types](https://racket.discourse.group/t/aloe-scheme-smalltalk-types/4367)
**Author:** [@dharmatech](https://racket.discourse.group/u/dharmatech)\ **Replies:** 5\ **Last updated:** [September 18, 2026, 10:19am UTC](https://racket.discourse.group/t/aloe-scheme-smalltalk-types/4367 "2026-09-18T10:19:23Z")
Hey y'all :man\_raising\_hand: In Scheme, we have: (proc arg ...) In ALOE, it's: (obj msg arg ...) It's an experiment in making everything about calling methods on objects instead of applying functions. And throwing t… --- ## [Thunk vs. lambda and doc confusion](https://racket.discourse.group/t/thunk-vs-lambda-and-doc-confusion/4388)
**Author:** [@gbellinoz](https://racket.discourse.group/u/gbellinoz)\ **Replies:** 13\ **Last updated:** [September 16, 2026, 11:56pm UTC](https://racket.discourse.group/t/thunk-vs-lambda-and-doc-confusion/4388 "2026-09-16T23:56:51Z")
Hi team, The Thunk glossary entry has a second example that is supposedly turning a function into a thunk, yet it uses the lambda keyword! But thunks exist as a keyword, so why use lambda? Am I missing something, or i… --- ## [PPA falling behind?](https://racket.discourse.group/t/ppa-falling-behind/4385)
**Author:** [@ToddOBryan](https://racket.discourse.group/u/ToddOBryan)\ **Replies:** 2\ **Last updated:** [September 16, 2026, 8:11pm UTC](https://racket.discourse.group/t/ppa-falling-behind/4385 "2026-09-16T20:11:00Z")
@samth The Racket PPA seems to have fallen behind by a couple of versions. Is it still working, or did a problem crop up? --- ## [CLI argument parser for Rhombus](https://racket.discourse.group/t/cli-argument-parser-for-rhombus/4386)
**Author:** [@halloleo](https://racket.discourse.group/u/halloleo)\ **Replies:** 1\ **Last updated:** [September 15, 2026, 3:58pm UTC](https://racket.discourse.group/t/cli-argument-parser-for-rhombus/4386 "2026-09-15T15:58:28Z")
I want to write a small CLI program in Rhombus. Does Rhombus have a CLI argument parser which can generate a help text and validate options and positional arguments? Many thanks for any help in advance. --- ## [\[TFP 2027\] Call for Papers for the 28th International Symposium on Trends in Functional Programming, Kyoto, Japan, March 2027](https://racket.discourse.group/t/tfp-2027-call-for-papers-for-the-28th-international-symposium-on-trends-in-functional-programming-kyoto-japan-march-2027/4382)
**Author:** [@peter88](https://racket.discourse.group/u/peter88)\ **Replies:** 0\ **Last updated:** [September 14, 2026, 9:52am UTC](https://racket.discourse.group/t/tfp-2027-call-for-papers-for-the-28th-international-symposium-on-trends-in-functional-programming-kyoto-japan-march-2027/4382 "2026-09-14T09:52:41Z")
TFP 2027 – Call for Papers (TFP 2027 | Trends in Functional Programming) Important Dates Submission deadline (pre-symposium, full papers): Thu 3rd Dec 2026 (AOE) Notification (pre-symposium, full papers): Thu … --- ## [How to require a submodule made with module\*?](https://racket.discourse.group/t/how-to-require-a-submodule-made-with-module/4380)
**Author:** [@joskoot](https://racket.discourse.group/u/joskoot)\ **Replies:** 3\ **Last updated:** [September 13, 2026, 8:09pm UTC](https://racket.discourse.group/t/how-to-require-a-submodule-made-with-module/4380 "2026-09-13T20:09:24Z")
trying to require a submodule made with module\* I get the following error: require: unknown module module name: (submod 'anonymous-module\[2096977\] aap) I have tried some variations on the line marked with \<---, but no… --- ## [16th RacketCon Early registration closes 13th September](https://racket.discourse.group/t/16th-racketcon-early-registration-closes-13th-september/4376)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 2\ **Last updated:** [September 13, 2026, 4:22pm UTC](https://racket.discourse.group/t/16th-racketcon-early-registration-closes-13th-september/4376 "2026-09-13T16:22:06Z")
Only a few day left for early tickets to the (sixteenth RacketCon) Professional $100.00 Student $25.00 (ends 13th September) Get your tickets now at https://www.eventbrite.com/e/racketcon-2026-tickets-1997181002140 --- ## [Futures not running parallely](https://racket.discourse.group/t/futures-not-running-parallely/4366)
**Author:** [@joskoot](https://racket.discourse.group/u/joskoot)\ **Replies:** 9\ **Last updated:** [September 12, 2026, 9:58am UTC](https://racket.discourse.group/t/futures-not-running-parallely/4366 "2026-09-12T09:58:02Z")
\#| I Try to use futures for parallelization. I have 12 processors. The task manager (Windows) tells me that only one processor is used. Question: why aren't the futures run parallely? I Run from the definitions window of… --- ## [Alternatives to scope sets for hygiene?](https://racket.discourse.group/t/alternatives-to-scope-sets-for-hygiene/4377)
**Author:** [@jgarvin](https://racket.discourse.group/u/jgarvin)\ **Replies:** 1\ **Last updated:** [September 7, 2026, 9:59pm UTC](https://racket.discourse.group/t/alternatives-to-scope-sets-for-hygiene/4377 "2026-09-07T21:59:33Z")
My understanding is that Racket hygiene being based on scope sets was chosen in part for historical reasons; e.g. the scope pruning scheme was added to be backwards compatible with existing idioms. I've skimmed the docs… --- ## [Bay Area Racket Meetup - September 5th, 3pm](https://racket.discourse.group/t/bay-area-racket-meetup-september-5th-3pm/4359)
**Author:** [@a11ce](https://racket.discourse.group/u/a11ce)\ **Replies:** 1\ **Last updated:** [September 5, 2026, 9:03pm UTC](https://racket.discourse.group/t/bay-area-racket-meetup-september-5th-3pm/4359 "2026-09-05T21:03:45Z")
Social event for people interested in the Racket programming language, other Lisps, functional programming, language-oriented programming and related topics. These will be monthly (first Saturday at 3pm) until RacketCon… --- ## [Racket meet-up(online): Saturday, 5 September 2026 at 18:00 UTC](https://racket.discourse.group/t/racket-meet-up-online-saturday-5-september-2026-at-18-00-utc/4363)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [September 5, 2026, 7:38pm UTC](https://racket.discourse.group/t/racket-meet-up-online-saturday-5-september-2026-at-18-00-utc/4363 "2026-09-05T19:38:28Z")
Everyone is welcome to join us for the :racket: Racket meet-up: Saturday, 5 September 2026 at 18:00 UTC :racket: :rhombus: :qi: :racket: :rhombus: :qi: In your timezone: 2026-09-05T18:00:00Z (UTC). (converter). Th… --- ## [3m (BC) build on GitHub stalling](https://racket.discourse.group/t/3m-bc-build-on-github-stalling/4373)
**Author:** [@ndykman](https://racket.discourse.group/u/ndykman)\ **Replies:** 0\ **Last updated:** [September 5, 2026, 1:08am UTC](https://racket.discourse.group/t/3m-bc-build-on-github-stalling/4373 "2026-09-05T01:08:56Z")
I have been running into this because I have made a few pull requests. It seems that the portlib core test just hangs. This was a concern because I thought my changes to rktio were the source, but this doesn't seem to be… --- ## [What do I need the Drawing Context for?](https://racket.discourse.group/t/what-do-i-need-the-drawing-context-for/4369)
**Author:** [@halloleo](https://racket.discourse.group/u/halloleo)\ **Replies:** 2\ **Last updated:** [September 3, 2026, 12:33pm UTC](https://racket.discourse.group/t/what-do-i-need-the-drawing-context-for/4369 "2026-09-03T12:33:00Z")
New here - and new to Rhombus! Via the pict module I generate little pictures. In the REPL they are displayed immediately. Now I try to write the pictures to a file, so that I can run the Rhombus program from a normal … --- ## [Call for Contributions: BOB 2027 (Berlin, Feb 26 - Deadline Nov 2)](https://racket.discourse.group/t/call-for-contributions-bob-2027-berlin-feb-26-deadline-nov-2/4370)
**Author:** [@mike](https://racket.discourse.group/u/mike)\ **Replies:** 0\ **Last updated:** [September 3, 2026, 8:40am UTC](https://racket.discourse.group/t/call-for-contributions-bob-2027-berlin-feb-26-deadline-nov-2/4370 "2026-09-03T08:40:31Z")
Racket and Rhombus content very welcome at BOB! BOB Conference 2027 - Call for Contributions "What happens when we use what's best for a change?" https://bobkonf.de/2027/cfc.html Berlin, Feb 26 Deadline: November 2, 20… --- ## [Rhombus : + on draw.Point](https://racket.discourse.group/t/rhombus-on-draw-point/4364)
**Author:** [@dharmatech](https://racket.discourse.group/u/dharmatech)\ **Replies:** 3\ **Last updated:** [September 3, 2026, 12:29am UTC](https://racket.discourse.group/t/rhombus-on-draw-point/4364 "2026-09-03T00:29:25Z")
Hey y'all :man\_raising\_hand: Is there a way to use + on draw.Point? So, something like this: #lang rhombus/static import: draw open operator ((a :: Point) + (b :: Point)): Point(a.x + b.x, a.y + b.y) def a = Po… --- ## [\-- SVG to pict --](https://racket.discourse.group/t/svg-to-pict/4358)
**Author:** [@soegaard](https://racket.discourse.group/u/soegaard)\ **Replies:** 2\ **Last updated:** [September 2, 2026, 5:52pm UTC](https://racket.discourse.group/t/svg-to-pict/4358 "2026-09-02T17:52:14Z")
Hi All, There is now a new library available for rendering SVG images. The two most useful functions are svg-file-\>pict and svg-string-\>pict. The renderer is implemented in Racket, so no external shared libraries ar… --- ## [UK Racket meet-up (London) Tuesday 1 September 2026 7:30pm](https://racket.discourse.group/t/uk-racket-meet-up-london-tuesday-1-september-2026-7-30pm/4360)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [September 1, 2026, 8:00am UTC](https://racket.discourse.group/t/uk-racket-meet-up-london-tuesday-1-september-2026-7-30pm/4360 "2026-09-01T08:00:59Z")
UK Racket meet-up (London) Tuesday 1 September 2026 7:30pm at The City Pride :pizza: 28 Farringdon Ln, London EC1R 3AU Join us for discussion and pizza. All welcome.:grin: λλλ --- ## [Registration is open for RacketCon 2026](https://racket.discourse.group/t/registration-is-open-for-racketcon-2026/4362)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 0\ **Last updated:** [August 29, 2026, 6:00pm UTC](https://racket.discourse.group/t/registration-is-open-for-racketcon-2026/4362 "2026-08-29T18:00:41Z")
Registration is open! Please register for RacketCon 2026 at https://www.eventbrite.com/e/racketcon-2026-tickets-1997181002140 Ticket prices Patron $150.00 Includes Saturday lunch and Saturday evening social event… --- ## [Comparing for in python and rhombus](https://racket.discourse.group/t/comparing-for-in-python-and-rhombus/4361)
**Author:** [@gus-massa](https://racket.discourse.group/u/gus-massa)\ **Replies:** 1\ **Last updated:** [August 29, 2026, 2:41pm UTC](https://racket.discourse.group/t/comparing-for-in-python-and-rhombus/4361 "2026-08-29T14:41:36Z")
I just lost like 1 hour debugging a program in python and I want to complain in spite it's the wrong forum. Anyway, I'd like to document it because the the reverse problem/surprise may be useful if someone is migrating f… --- ## [What is the current rash status?](https://racket.discourse.group/t/what-is-the-current-rash-status/4355)
**Author:** [@hnmdijkema](https://racket.discourse.group/u/hnmdijkema)\ **Replies:** 6\ **Last updated:** [August 27, 2026, 3:23pm UTC](https://racket.discourse.group/t/what-is-the-current-rash-status/4355 "2026-08-27T15:23:03Z")
Hi all, I’ve been working on some things like git commands and makefile functionality. This makes it possible to do a complete workflow from DrRacket. Next I was looking for a way to use the racket REPL like a shell. I… --- ## [Furtle page missing](https://racket.discourse.group/t/furtle-page-missing/4354)
**Author:** [@jsampson45](https://racket.discourse.group/u/jsampson45)\ **Replies:** 2\ **Last updated:** [August 23, 2026, 12:48pm UTC](https://racket.discourse.group/t/furtle-page-missing/4354 "2026-08-23T12:48:05Z")
The page about Furtle, a turtle graphics module, is 404 (https://docs.racket-lang.org/furtle/index.html). Does Furtle exist? --- ## [How can I load code to be able to test all of it?](https://racket.discourse.group/t/how-can-i-load-code-to-be-able-to-test-all-of-it/4351)
**Author:** [@Greg\_Davidson](https://racket.discourse.group/u/Greg_Davidson)\ **Replies:** 8\ **Last updated:** [August 23, 2026, 12:44pm UTC](https://racket.discourse.group/t/how-can-i-load-code-to-be-able-to-test-all-of-it/4351 "2026-08-23T12:44:30Z")
I'd like to test my code in module.rkt with tests in module-test.rkt and the rackunit documentation advises I use (require rackunit "module.rkt") in module-test.rkt Alas, this only allows me to test things bound to s… --- ## [Another better lower bound for n=17 square packing](https://racket.discourse.group/t/another-better-lower-bound-for-n-17-square-packing/4353)
**Author:** [@gus-massa](https://racket.discourse.group/u/gus-massa)\ **Replies:** 2\ **Last updated:** [August 22, 2026, 6:31pm UTC](https://racket.discourse.group/t/another-better-lower-bound-for-n-17-square-packing/4353 "2026-08-22T18:31:24Z")
I made an improvement of a recent blog post by Sam Burns where he uses ChatGPT 5.6 Sol to increase the lower bound from 4.4452... to 4.4811 that uses a program in Python as part of the proof. I split my result in two pa… --- ## [Brandx, a new library for OOP, interfaces, generics, and more](https://racket.discourse.group/t/brandx-a-new-library-for-oop-interfaces-generics-and-more/4350)
**Author:** [@ryanc](https://racket.discourse.group/u/ryanc)\ **Replies:** 0\ **Last updated:** [August 21, 2026, 8:44pm UTC](https://racket.discourse.group/t/brandx-a-new-library-for-oop-interfaces-generics-and-more/4350 "2026-08-21T20:44:43Z")
I'm pleased to announce brandx, a new Racket library for OOP, interfaces, generics, components, and more. The docs are available online, with an introduction including multiple examples. (Thanks to Matthias for comments … --- ## [Example of tack/untack not shown when inside a let form](https://racket.discourse.group/t/example-of-tack-untack-not-shown-when-inside-a-let-form/4349)
**Author:** [@joskoot](https://racket.discourse.group/u/joskoot)\ **Replies:** 1\ **Last updated:** [August 21, 2026, 7:24am UTC](https://racket.discourse.group/t/example-of-tack-untack-not-shown-when-inside-a-let-form/4349 "2026-08-21T07:24:38Z")
Is there a special reason why in the let-form no tack/untack option is shown when I right-click on letter b? As the figure shows, without let the option appears and works. Just curious. --- ## [UK Racket meet-up (London) Tuesday 18 August 2026 7:30pm](https://racket.discourse.group/t/uk-racket-meet-up-london-tuesday-18-august-2026-7-30pm/4346)
**Author:** [@spdegabrielle](https://racket.discourse.group/u/spdegabrielle)\ **Replies:** 1\ **Last updated:** [August 18, 2026, 7:41am UTC](https://racket.discourse.group/t/uk-racket-meet-up-london-tuesday-18-august-2026-7-30pm/4346 "2026-08-18T07:41:02Z")
UK Racket meet-up (London) Tuesday 18 August 2026 7:30pm at The City Pride :pizza: 28 Farringdon Ln, London EC1R 3AU Join us for discussion and pizza. All welcome.:grin: λλλ See the Racket Calendar for more eve… [Next page](https://racket.discourse.group/latest.md?page=1)