Juvix

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LICENSE Juvix Mascot

Description

Juvix is a research programming language created by Heliax as a first step toward creating more robust and reliable alternatives for formally verified smart contracts than existing languages. The Juvix language is constantly evolving, open-source, functional, and statically typed with special support for compiling validity predicates to the C language, which can be deployed to various distributed ledgers including Anoma.

The Juvix language and related tools are documented in the Juvix book. To write and test Juvix programs, you can use your favorite text editor and the juvix command line tool. However, we recommend using the juvix-mode in Emacs or the plugin in VSCode.

First examples of programs written in Juvix

The following links are clickable versions of their corresponding Juvix programs. The HTML output is generated by running juvix html --recursive FileName.juvix.

The Juvix standard library contains common functions that can be used in Juvix programs.

Quick Start

Installing Juvix on MacOS

The easiest way to install Juvix on MacOS is by using Homebrew.

To install the homebrew-juvix tap, run:

brew tap anoma/juvix

To install Juvix, run:

brew install juvix

After installing Juvix, you might want to try our doctor to check your system setup:

juvix doctor

Helpful information on the shell can also be obtained by running:

brew info juvix

Building Juvix from the sources

To install Juvix from the sources, you must download the Github repository. Then, the program can be installed with the following commands. We assume have Stack installed.

git clone --recursive https://github.com/anoma/juvix.git
cd juvix
stack install

If the installation succeeds, you must be able to run the Juvix command from any location. To get the complete list of commands, please run juvix --help.

On MacOS, you can alternatively run the following command for Homebrew. The flag --HEAD used below is optional, mostly to build the latest version of Juvix in the main branch on Github.

brew install --build-from-source --HEAD juvix --verbose

The Hello World Example

In the following example a Juvix file is compiled to Wasm. Please check out the documentation Installing dependencies for instructions on how to setup your environment for compiling Juvix. You can also run juvix doctor to check your system setup.

-- HelloWorld.juvix
module HelloWorld;

open import Stdlib.Prelude;

main : IO;
main ≔ putStrLn "hello world!";

end;

Then, run the following commands at the location folder of the file HelloWorld.juvix:

juvix compile HelloWorld.juvix
wasmer HelloWorld.wasm

You should see the output: hello world!

The Juvix programming language

Juvix allows us to write programs with a high degree of assurance. The Juvix compiler runs several static analyses during the compilation phase to guarantee no runtime errors. Analyses permormed during this phase include scope, termination, arity, and type checkiqng. As a result, functional programs, especially validity predicates, can be written with greater confidence that they will be free of runtime errors.

Some of the language features in Juvix include:

  • unicode syntax
  • parametric polymorphism
  • inductive and parametric data types
  • higher-order functions
  • implicit arguments
  • holes in expressions
  • axioms for non-computable terms

Additionally, the foreign and compile blocks syntax enable developers to compile a program to different backends including the C language. The Juvix module system further permits splitting programs into several modules to build libraries which can be later documented by generating HTML files based on the codebase, see for example, the Juvix standard library's website. For futher details, please refer to the Juvix book which includes our latest updates.

Coming soon

For the language:

  • lambda expressions
  • let expressions
  • tail call optimization
  • inference for mutually recursive functions
  • compilation to circuits
  • coverage checking (i.e. exhaustiveness and useless clauses)

For the compiler:

  • Init command
  • Better documentation tool: juvix doc MyFile.juvix

Community

We would love to hear what you think of Juvix! Join us on the Anoma Discord.