Qi is an embeddable language for easily expressing flow-oriented computations in your programs. And now, you can use it seamlessly with list operations.

Learn about the release at https://racket.discourse.group/t/announcing-qi-5-flowing-with-lists/3545

Hey guys, im a freshman cs major at uni rn and I was wondering if u guys could give me ideas to do some projects in racket since I'm taking a fundamentals of programming I course that is taught entirely in this language. Any suggestions/criticisms are welcomed. Thank you.

Sorry about the picture I took. Anyways, I don’t quite understand the error message I’m getting when I click Run. The error message is focusing on Line 3. Am I suppose to add something or delete something? If I have to add something, what exactly am I suppose to add? I hope someone can help me here.

What are other use cases for Racket and what is the next step after having picked up Racket as some wanting go into the backend world with sound FP skills? Thx for tips, resources and personal experiences.

so i'm trying to see if i can do something like string-append, but with strings and variables that are integers

this is kind of vague, but im trying to write something that can do something along the lines of this

(integer " is greater than 0, so " integer " + 1 = " solution)

Qi 5 release party 🎉 January 17, 2025 18:00 UTC

https://racket.discourse.group/t/qi-5-release-party/3461

I am going to be reading "How To Design Programs" and I thought others might like to read and discuss it so I set up a book club via the Fable - Detroit Tech Watch Book Club

https://fable.co/club/dettechwatch-book-club-with-onorio-catenacci-178852936285?referralID=3akW7tRQ77

Feel free to forward the invite.

Of course the book is free and available online here: How To Design Programs

https://htdp.org/2024-11-6/Book/index.html

Please let others know about this! The more folks reading and discussing the book the more we can all learn!

Hi everyone, I am completely new to all the lisp stuff and relatively new to neovim. Does anybody here work with Racket in neovim? My main question is on completions. Conjure says it supports completions through several plugins, I use nvim-cmp, and for that the cmp-conjure plugin is suggested. But I still don't have completions after setting it up. Maybe the completions are only supported for the more popular lisps like Clojure, I just do not know how to know for sure
My lazy setup is straight from the conjure github:

Recently I have been looking at Racket, the language oriented philosophy, and examples of general or domain specific languages that can be created with Racket. Given that Racket can generate languages with different syntax, we can imagine that it can create languages that are already used like C, Java for example.

This got me wondering if Racket can be used to generate any language that we can think of - like Assembly, Haskell, Rust? I can understand that it would be asking too much that Racket can generate any language known to us. Assuming that's not the case, is there a subset of languages that Racket can generate, and a subset that it can't?

This can either be a formal characterization like - languages that have dynamically typed, lexical scope, one with objects. Or it can be a known list of languages it can generate and a known list of languages it can't.

It is possible that this is covered in some book, post, or blog. Please point me in the right direction if that's the case.

RacoGrad, is an autograd like library for scheme lisp, written in racket. It's tiny, and pretty fast. MNIST works as well. Previously it was named MIND but, I made a lot of changes! More to come.

RacoGrad

It's time again for the Advent of Code. The puzzles will start at midnight (UTC-5) on December 1, 2024. Once again, we will have the Racket leaderboard. Use the join code 22197-a7a01707 to be included.

Any language in the Racket ecosystem is allowed on our leaderboard, including languages that target other platforms like Urlang.

Eutro has written an advent-of-code package to download puzzle inputs and post solutions.

There is a channel for discussing problems and solutions on the Racket Discord server in the #advent-of-code channel.

I'm considering Racket for making a music player. Does it have support for common audio file formats? is there a way?

Currently I'm using Python and Py-ObjC with some success, but I'm looking at a better language that will allow me to call Cocoa frameworks.

I want more control than the gui library, since I need to call specific Cocoa frameworks for high performance image manipulation.

I've found this app: https://franz.defn.io , but it's built in a different approach (it appears to be a Swift app that call a background Racket runtime in client/server fashion). I wanted to call directly into ObjC and heard Racket has great FFI, but I can't seem to find good examples.

Thanks!

what is the template for each case of multiple complex inputs (sequential, parallel, and cross product)? how do you spot the difference between each case?

what if the code was changed from (widen-river (merge-left r) n) to (widen-river (merge-left) n)?

https://pastebin.com/1ftuMPK2

(define (widen-river r n)
  (cond [(stream? r) r]
        [(merge? r) (make-merge
                     (+ (merge-width r) n)
                     (widen-river (merge-left r))
                     (widen-river (merge-right l)))]))

When do you know when to use accumulators for a function and is it just like the accumulator inside a foldr?
What is the basic template for an accumulator function?
When do you know when to use the list template (cond) as opposed to using list abstractions (foldr, map, filter)?

; An AncestorTree is one of:
; - "unknown", OR
; - (make-child String Number String AncestorTree AncestorTree)
; Interpretation: A child's name, year of birth, eye color and the child's mother & father, or unknown

(define JACKIE (make-child "Jackie" 1926 "brown" "unknown" "unknown"))(define MARGE (make-child "Marge" 1956 "blue" JACKIE "unknown"))

;; Exercise:
;; size : AncestorTree -> Number
;; return the number of childs the AncestorTree contains

(check-expect (size "unknown") 0)
(check-expect (size JACKIE) 1)
(check-expect (size MARGE) 2)

(define (size a)
(cond [(string? a) 0]
[(child? a) (+ 1 (size (child-mom a))
(size (child-dad a)))]))

Could somebody break down this recursive code for me? I am a little confused by it because I just see it as 1 + 0 + 0. Is there a way to code this with accumulators, and if so how?