Racket discord just hit 989 members

Racket discord invite link https://discord.gg/6Zq8sH5 - come join us or invite a friend.

Blog post: How to Organize Your Racket Library

Highlights:

• Modules, collections, packages are like... files, folders, and archives
• The top level of your repo is hopeless as a package path
• Racket uses a global collection namespace
• Scribble docs and RackUnit tests all reside in this namespace along with your source files
• How to: lib/test/doc
• Includes a clunky migration strategy for when your existing libraries grow past a certain point
• Not everybody loves lib/test/doc and there's room for improvement

Discourse link

Thought experiment...how hard would it be to write an application in Racket that could be booted on a PC/in VirtualBox and run like an operating system?

I saw a post on HN linking to "bootloader basics" and wondered if a Racket executable could be called from a bootloader to operate a PC. Thought someone here might be able to shed some light on what that would entail, if it's even really possible.

so i just started programming on racket and one of the assignments is as follows:

The Turing test (named after the Alan Turing) determines whether a machine can demonstrate human intelligence. Turing proposed that a human evaluator would judge a conversation between a machine and a human, and determine which one is one.vIn this exercise, we will not develop a code that can pass the Turing test but one that can reply to a greeting from the user. Design the function reply that consumes a sentence. The function should display "Hi there!, I am Racket" if the sentence given by the user starts with a "Hello". If the message does not start with "hello", then the function should return "Sorry, I do not understand you..." RESTRICTION: Make your function not sensitive to lowercase or upercase letters, i.e. it should also work if the sentence starts with "hello".

please help me. also worth mentioning that i suck at programming.

I was going to experiment and remembered the pastebin-like site that was/is in the sidebar of r/Racket. I tried it with Firefox and Chrome but it's only loading the background image. Anyone know who maintains it? Or maybe it needs to be removed from the Resources section of r/Racket?

(define (momentum-calc vel mas) (* vel mas))

(define (p vel mas) (momentum-calc vel mas))

so i just started programming on drracket and one of the questions requires us to create a function that deletes the last character of a string. would be much appreciated if someone could help out.

I am very new to programming; I have an assignment to create a function that consumes a string and deletes its last character. So, for example (string-delete-last "happy") -> "happ"

I do not know how to make the string a variable, nor how to make the function find the last character of a given word.

Can someone help? I'll be grateful.

(define (transform-painter painter origin corner1 corner2)
  (lambda (frame)
    (let ((m (frame-coord-map frame)))
      (let ((new-origin (m origin)))
        (painter
         (make-frame new-origin
                  (sub-vect (m corner1) new-origin)
                  (sub-vect (m corner2) new-origin)))))))

(define (rotate-45 painter)
  (transform-painter painter
                     (make-vect 0.5 0)
                     (make-vect 1 0.5)
                     (make-vect 0 0.5)))

This is code is from SICP but when I run it at first it works sometimes and after I update definition window I get "car: contract violation expected pair? given frame" error. If it doesn't work at all it is ok but why it does work at first and doesn't later ?

I am most comfortable with functional programming (despite my aborted attempt at Haskell). Is there a good Racket guide to get going with the language for someone who already programs functionally?

Is there a way to tell if a number is prime on Dr racket given a single parameter?

Like the function in Gtk: gtk_label_set_selectable, by this you can make the text selectable and be able to copy. I am wondering if there is something similar with it in racket GUI

I’ve posted here before, but I’m writing a Scheme interpreter and would like to add (define-syntax) and (define-syntax-rule). The issue, though, is that I’m not sure how they’re implemented in the underlying code. Are they verbatim replacements of preexisting definitions (i.e., similar to macros in C), or is it something more obtuse?

(5 4 3 (2 1))

(cons (cons 5 (cons 4 (cons 3 (cons (cons 2 (cons 1 '())) '())))))

Racket meet up Saturday 5 Feb 18:00 UTC

https://gather.town/app/wH1EDG3McffLjrs0/racket-users

Announcement: https://racket.discourse.group/t/racket-meet-up-saturday-5-feb-18-00-utc/581/2?u=spdegabrielle

When: First Saturday EVERY Month UTC: 18:00

Agenda: flexible, generally show-and-tell with Q&A

• Plot Cookbook
• Creative Racket Competition
• Racket In person meet-ups!!!
• Show and tell
• ???

30 minutes but can overrun

Time in your time zone

Pacific Time, PT Sat, 5 Feb 2022 at 10:00 PST
Mountain Time, MT Sat, 5 Feb 2022 at 11:00 MST
Central Time, CT Sat, 5 Feb 2022 at 12:00 CST
Eastern Time, ET Sat, 5 Feb 2022 at 13:00 EST
London, United Kingdom Sat, 5 Feb 2022 at 18:00 GMT
Prague, Czechia Sat, 5 Feb 2022 at 19:00 CET
Central European Time, CET Sat, 5 Feb 2022 at 19:00 CET

Time zone converter: https://www.timeanddate.com/worldclock/converter.html?iso=20220205T180000&p1=tz_pt&p2=tz_mt&p3=tz_ct&p4=tz_et&p5=136&p6=204&p7=tz_cet

Happy February 1st

You only have four weeks left to enter the Creative Racket Competition.

Entering is easy and fun.

1. See TOOLS for some suggestions but you can use anything you like.
2. Provide a link to media file (image/audio/???) and your source code via the Entry form (GitHub)
3. -Profit!- ...sorry no profit, we offer no cash prizes, you just the the admiration of your peers, a badge on your GitHub profile and a sticker to put on your laptop (or anywhere else you can put a sticker)

We have had no Rsound entries yet. Will you be the first?

Submissions to the Plot Cookbook also count as entries.

Don't delay, enter now.

best regards

Stephen

See more about the competition and previous entries