Futhark by example
futhark-lang.org97 points by tosh 10 hours ago
97 points by tosh 10 hours ago
I was so confused by the word factorial in the first example for a language, but decided to click it and just see what it means
Turns out, Futhark != https://en.wikipedia.org/wiki/Futhark (runes, old germanic alphabet)
That's like calling your programming language Latin?! The title could use some disambiguation...
Futhark is really such a great idea. I'm not convinced that dependent types are worth the cognitive overhead in general, but it's definitely worth it to include the length as part of the type information for dynamic arrays, e.g.:
concat(Vec<T, n>, Vec<T, m>) -> Vec<T, n+m>
matmul(Mat<T, n, m>, Mat<T, m, l>) -> Mat<T, n, l>
head(Vec<T, n+1>) -> (T, Vec<T, n>)
Here they are in Futhark:
val concat [n] [m] 't : (xs: [n]t) -> (ys: [m]t) -> *[n + m]t
val matmul [n] [m] [l] 't : (xs: [n][m]t) -> (ys: [m][l]t) -> *[n][l]t
val head [n] 't : (x: [n]t) -> t
val filter [n] 'a : (p: a -> bool) -> (as: [n]a) -> *[]a
The Pyrefly type checker is starting to work on this kind of shape hinting - so far it only works on Torch but I believe the plan is for it to work with other array packages (eg. JAX, NumPy)
Shape functions and shape analysis are basically mundane infra in almost every ML compiler/language/DSL.
You can do this with templates in C++ and generics in Rust I'm pretty sure. I think the Eigen C++ library supports this. (I have yet to do a linear algebra heavy Rust project, so I can't speak to the options that exist there.)
I'm talking about cases where the array size is not known at compile time. For example, say the user passes in a list of numbers as command line arguments. Then we have
argv: Vec<String, argc>
nums: Vec<Int, argc>
Yeah, C++ arrays are literally that.
Arrays are not dynamically sized though (handling runtime sizes) and don’t have efficient append/concat. The point of the dependent types is that you can have the type system track that concat creates an M+N length vector, sort preserves length (and adds a sorted guarantee that slice preserves), etc. Sure you can do a lot with templates, but that’s advanced templates not just “C++ arrays” in a throwaway “literally that” way.
It would be nice to not name your language after another language. (Yes I know it's a script, that doesn't change my point). I came here expecting something else.
Yeah, when naming your language, it's important to keep mind the expectations of people seeing headlines about articles about your language on blog aggregation sites :^)
Now I'm thinking about "Smalltalk by Example" and "Slang by Example"
Jackson Crawford's youtube channel is very helpful academic source.
For those that don't know, Futhark is comes from the first 6 letters of the runic alphabet (F, U, Þ, A, R, K)
Was expecting to see some examples of how to read runes, but I am nonetheless equally satisfied.
Same. Thought I had a copy of Uthark [1][2] on my shelf too but alas I seem to have only retained Svartkonst [3] during the tragic downsizing of my library.
[1] https://archive.org/details/karlsson-thomas-uthark-nightside...
[2] https://www.84cxrarebooks.com/pages/books/090763/t-ketola-th...
[3] https://www.miskatonicbooks.com/product/thursakyngi-iv-svart...
Futhark is pretty great! And I have to say that the maintainer is insanely quick. It has happened on more than one occasion that I reported a bug and it's solved within the day. I have been using Futhark in prod for two years now and never had serious problems.
Futhark is a glimmer of light in the wasteland of C/C++ styled low level GPU languages.
Couldn’t have chosen a more difficult (and ambiguous) name to pronounce, could you? It almost sounds like a curse that I often hear people say out in the bad streets of New York City.
Elder [0] and Younger [1] Futhark (or Fuþark) are the name of two runic writing systems used by Germanic and Scandinavian Vikings. The name Futhark is a combination of the first 6 runes /f/, /u/, /ð/, /ɑ/, /r/, and /k/. Similar to how you get the name "alphabet" from the first two letters of Greek's writing system.