<img alt="leo" width="1412" src="https://github.com/ProvableHQ/leo/raw/leo-fmt-v4.3.2/resources/leo-banner.png">

The Leo Programming Language

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Leo is an imperative, statically-typed programming language built for writing private applications.

Table of Contents

• 🍎 Overview
• ⚙️️ Build Guide
  • 🦀 Install Rust
  • 📦 Download using Cargo
  • 🐙 Build from Source Code
  • 🦁 Update from Leo
• 🚀 Quick Start
• 🧰 Troubleshooting
• 📖 Documentation
• 🤝 Contributing
• 🛡️ License

🍎 Overview

Welcome to the Leo programming language.

Leo provides a high-level language that abstracts low-level cryptographic concepts and makes it easy to integrate private applications into your stack. Leo compiles to circuits making zero-knowledge proofs practical.

The syntax of Leo is influenced by traditional programming languages like JavaScript, Scala, and Rust, with a strong emphasis on readability and ease-of-use. Leo offers developers with tools to sanity check circuits including unit tests, integration tests, and console functions.

Leo is one part of a greater ecosystem for building private applications on Aleo. The language is currently in an alpha stage and is subject to breaking changes.

⚙️️ Build Guide

🦀 Install Rust

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

• macOS or Linux: bash 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.

📦 Download using Cargo

If you don't intend to work on the Leo compiler itself, you can install the latest Leo release with:

cargo install leo-lang leo-fmt leo-lsp

Now to use leo, in your terminal, run:

leo

🐙 Build from Source Code

If you'd like to install the latest unreleased top of tree Leo, you can build from source code as follows:

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

# Install 'leo' and bundled plugins
cargo install --path crates/leo
cargo install --path crates/fmt

🦁 Update from Leo

You can update Leo and its plugins to the latest released version using the following command:

leo update

Note that if you were using a prerelease version of Leo, this will overwrite that with the latest released version.

Now to check the version of leo, in your terminal, run:

leo --version

🚀 Quick Start

Use the Leo CLI to create a new project

# create a new `hello-world` Leo project
leo new helloworld
cd helloworld

# build & setup & prove & verify
leo run main 0u32 1u32

The leo new command creates a new Leo project with a given name.

The leo run command will compile the program into Aleo instructions and run it.

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

🧰 Troubleshooting

If you are having trouble installing and using Leo, please check out our guide.

If the issue still persists, please open an issue.

📖 Documentation

• Leo ABNF Grammar
• Homepage

🤝 Contributing

Please see our guidelines in the developer documentation

🛡️ License

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