The Leo Programming Language

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

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.

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.

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

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

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

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.

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

If the issue still persists, please open an issue.

• Leo ABNF Grammar
• Homepage

Please see our guidelines in the developer documentation

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