Pinned
# RacketCon 2026: call for presentations
Calling racketeers new or experienced, we want to hear from you.
Are you unsure or just new to presenting? let us know - [email protected] - and we will do our best to help you.
Racket (& Rhombus)
@racketlang
Racket & Rhombus programming languages. Racket - the Language-Oriented Programming Language, Rhombus - easy to use and uniquely customizable.
- # UK Racket meet-up (London) Tuesday 18 August 2026 7:30pm at The City Pride 🍕 28 Farringdon Ln, London EC1R 3AU Join us for discussion and pizza. All welcome.😁 #racket #lisp #rhombus racket.discourse.group/t/uk-racket-me…
- Still considering presenting at RacketCon? Contact us **now** at [email protected]
![```python
// efficient functional data structures
class Tree(val, children :: List.of(Tree)):
method flatten(): // O(N log N) for N `val`s
for fold(lst = [val]) (child in children):
// because append with `++` is O(log N)
lst ++ child.flatten()
Tree(1, [Tree(2, [Tree(4, [])]),
Tree(3, [Tree(5, [])])])
.flatten() // ⇒ [1, 2, 4, 3, 5]
```
(the 'python’ syntax highlighting in most markdown-like environments is sufficient for Rhombus)
Rhombus Programming Language
https://rhombus-lang.org
#rhombus](https://pbs.twimg.com/media/HNg8tgeWQAA9T4u?format=webp&name=medium)
![```
// pattern matching in all binding positions
class Posn(x, y)
fun flip_all([Posn(x, y), ...]):
[Posn(y, x), ...]
flip_all([Posn(1, 2), Posn(3, 4)])
// ⇒ [Posn(2, 1), Posn(4, 3)]
flip_all([Posn(5, 6)])
// ⇒ [Posn(6, 5)]
```
https://rhombus-lang.org](https://pbs.twimg.com/media/HNRgFbwXcAAT2De?format=webp&name=medium)
