The Leo Programming Language

Leo is a functional, statically-typed programming language built for writing private applications.

Table of Contents

• 1. Overview
• 2. Build Guide
  • 2.1 Install Rust
  • 2.2a Build from Crates.io
  • 2.2b Build from Source Code
• 3. Quick Start
  • 3.1 Zero Knowledge in One Line
• 4. Flying Tour
• 5. License

1. Overview

Welcome to the Leo programming language.

Leo exists to provide a simple high-level language that compiles to a rank one constraint system (R1CS) circuit. With Leo, you can write circuits to support zero-knowledge tokens, private stable coins, and decentralized marketplaces.

The syntax of Leo is influenced by JavaScript, Python, Scala, and Rust with a strong emphasis on readability and ease-of-use.

2. Build Guide

2.1 Install Rust

We recommend installing Rust using rustup. You can install rustup as follows:

• macOS or Linux:

  curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
  

• Windows (64-bit):

  Download the Windows 64-bit executable and follow the on-screen instructions.

• Windows (32-bit):

  Download the Windows 32-bit executable and follow the on-screen instructions.

2.2a Build from Crates.io

We recommend installing Leo this way. In your terminal, run:

cargo install leo

Now to use Leo, in your terminal, run:

leo

2.2b Build from Source Code

Alternatively, you can install snarkOS by building from the source code as follows:

# Download the source code
git clone https://github.com/AleoHQ/leo
cd leo

# Build in release mode
$ cargo build --release

This will generate an executable under the ./target/release directory. To run snarkOS, run the following command:

./target/release/leo

3. Quick Start

Use the Leo CLI to create a new project

leo new hello_world
cd hello_world

This creates a directory with the following structure:

hello_world/
├── Leo.toml # Your program manifest
├── inputs/ 
│ └── hello_world.in # Your program inputs
└── src/    
  └── main.leo # Your program file

Let's run the project.

3.1 Zero Knowledge in one line

leo run

This command will compile the program, generate keys for a trusted setup, fetch inputs, generate a proof and verify it.

Congratulations! You've just run your first Leo program.

4. Flying Tour

WIP

5. License