Kind is a pure functional programming language and proof assistant.

Getting started • Examples • Installation

 

Getting started

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)

Theorems can be proved inductively, as in Agda and Idris:

// Black Friday Theorem. Proof that, for every Nat n: n * 2 / 2 == n.
BlackFridayTheorem (n: Nat)     : Equal Nat (Nat.half (Nat.double n)) n
BlackFridayTheorem Nat.zero     = Equal.refl
BlackFridayTheorem (Nat.succ n) = Equal.apply (x => Nat.succ x) (BlackFridayTheorem n)

For more examples, check the Wikind.

Installation

First, install Rust first, then enter:

cargo install kind2

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 a rust crate using HVM.
To-KDL	kind2 to-kdl file.kind2	Generates a .kdl file. Can then be deployed to Kindelia.

The rust crate can be generated via HVM:

kind2 to-hvm file.kind2 > file.hvm
hvm compile file.hvm

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