Lithe
Lithe is a smart-contract language for the EVM. Entrypoints are state transitions with explicit effects, typed failures, and deterministic storage. The compiler enforces the security rules that Solidity leaves to convention.
[!WARNING]
Lithe is in early development and experimental. The language, standard library, and compiler output can change without notice, and neither the compiler nor the standard library has been audited.
storage is record {
count : uint;
}
external view function get() : uint is
storage.count
external function inc() is {
storage.count := storage.count + 1;
}
- External calls are deferred. A state-changing call to another contract runs after the entrypoint has finished its own work, so a callee never sees half-updated state.
- Typed, declared failures. Every external function lists the errors it can raise, and the compiler checks the list is complete.
- Checked effects.
pure and view are verified against their bodies.
- Formal verification. Specs beside the contract are proved with
lithe prove, against the bytecode the compiler emits.
- Deterministic storage. The default layout matches Solidity's; named domains sit at ERC-7201 roots.
- Modules, not inheritance, and built-in UUPS upgrades.
- Smaller bytecode. About 32% less runtime code than optimized
solc across real contracts.
Getting started
Install the latest release (Linux or macOS):
curl -fsSL https://lithe-lang.org/install.sh | sh
Or build the compiler with a recent stable Rust toolchain:
cargo build --release
export PATH="$PWD/target/release:$PATH"
Compile a contract and print its ABI:
lithe compile counter.lithe # creation bytecode as hex
lithe abi counter.lithe
lithe compile src # Foundry-style artifacts in ./out
Run lithe with no arguments for every command. lithe prove runs the Z3 solver, which the build compiles in; that needs CMake, Python 3, and a C++ compiler.
Repository
| Path | Contents |
|---|
src/ | the compiler, CLI, and LSP server |
std/ | the standard library, embedded in the compiler at build time |
docs/ | the documentation site (Vocs); see docs/README.md |
playground/ | the compiler built to WebAssembly for the docs site's browser playground |
examples/ | example contracts |
bench/ | Lithe and Solidity versions of the same contracts, for size and gas comparison (bench/run.py) |
extensions/ | editor support (a TextMate grammar, a VS Code extension, and a Recur bundle; see Editors) and the Hardhat plugin |
fuzz/ | extra programs for the differential tests |
Run the tests with cargo test.
Documentation
Start with Installation and first contract, then The transition model and Lithe by Example.
Contributing
Pull requests from outside the team aren't accepted. To report a bug or ask for a feature, open an issue. To report a vulnerability, follow SECURITY.md.
License
Licensed under the Apache License, Version 2.0.
