Kind2
Kind2 is a functional programming language and proof assistant.
It is a complete rewrite of Kind1, based on
HVM, a lazy, non-garbage-collected and massively parallel virtual
machine. In our benchmarks, its type-checker outperforms every
alternative proof assistant by a far margin, and its programs can offer exponential speedups over Haskell's GHC. Kind2
unleashes the inherent parallelism of the Lambda
Calculus to become the ultimate programming language of
the next century.
Welcome to the inevitable parallel, functional future of computers!
Examples
Pure functions are defined via equations, as in Haskell:
// Applies a function to every element of a list
map <a> <b> (list: List a) (f: a -> b) : List b
map a b Nil f = Nil
map a b (Cons head tail) f = Cons (f head) (map tail f)
Side-effective programs are written via monads, resembling Rust and TypeScript:
// Prints the double of every number up to a limit
Main : IO (Result () String) {
ask limit = IO.prompt "Enter limit:"
for x in (List.range limit) {
IO.print "{} * 2 = {}" x (Nat.double x)
}
return Ok ()
}
Theorems can be proved inductivelly, as in Agda and Idris:
// Black Friday Theorem. Proof that, for every Nat n: n * 2 / 2 == n.
black_friday_theorem (n: Nat) : Equal Nat (Nat.half (Nat.double n)) n
black_friday_theorem Nat.zero = Equal.refl
black_friday_theorem (Nat.succ n) = Equal.apply (x => Nat.succ x) (black_friday_theorem n)
For more examples, check the Wikind.
Usage
First, install Rust first, then enter:
cargo install kind2
Warning:
New versions probably are not in cargo, so you can install the current version of kind2 by following these instructions:
- Install Rust Nightly Toolchain
- Clone the repository
cargo install --path crates/kind-cli --force
Then, use any of the commands below:
| Command | Usage | Note |
|---|---|---|
| Check | kind2 check file.kind2 |
Checks all definitions. |
| Eval | kind2 eval file.kind2 |
Runs using the type-checker's evaluator. |
| Run | kind2 run file.kind2 |
Runs using HVM's evaluator, on Rust-mode. |
| To-HVM | kind2 to-hvm file.kind2 |
Generates a .hvm file. Can then be compiled to C. |
| To-KDL | kind2 to-kdl file.kind2 |
Generates a .kdl file. Can then be deployed to Kindelia. |
Executables can be generated via HVM:
kind2 to-hvm file.kind2
hvm compile file.hvm
clang -O2 file.c -o file
./file
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If you need support related to Kind, email support.kind@kindelia.org
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For Feedbacks, email kind@kindelia.org
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To ask questions and join our community, check our Discord Server.
