valida-rs

This crate is to be used as a dependency in a Valida project. It provides the entry point for the program and an IO library that works on Valida. This version is tested to be compatible with valida-toolchain v0.7.0-alpha.

The entrypoint! macro

The entrypoint! macro:

• Sets up a deterministic random number generator: It ensures that when rand functions are called, they are fixed to a specified seed and thus are deterministic. This is required for the program to be provable.
• Creates a new entry point that wraps the user's main function: This is required because we need to make Rust call this main function, the standard Rust main function does not work on Valida.

For projects that require rand

Use the main branch if you need randomness. Add the following to your src/main.rs:

#![no_main]

valida_rs::entrypoint!(main);

The #![no_main] (with !) is an inner attribute that applies to the entire crate, telling the Rust compiler not to look for a standard main function entry point. We need this because we are providing a custom entry point.

Add the following to your Cargo.toml:

[dependencies]
valida-rs = { git = "https://github.com/lita-xyz/valida-rs.git", tag = "v0.7.0-alpha" }
getrandom = "0.2.15" # or the current version
rand = "0.8.5" # or the current version

The io library

This library provides common IO functions that work on Valida. See io.rs for the full list of available functions. Note that not all stdlib IO functions are supported yet. Also, most of the Rust standard std::io module is not supported at the moment. If you use them, they may silently not work.

For projects with no other dependencies

If you would like to use IO functionalities in your project, you will want to use the no-deps branch. If you need randomness and/or serialization/deserialization of data, use the main branch. See above for more details.

To use this branch, add the following to your Cargo.toml:

[dependencies]
valida-rs = { git = "https://github.com/lita-xyz/valida-rs.git", tag = "v0.7.0-alpha-no-deps" }

Also, in your src/main.rs, add the following:

#![no_main]

#[no_mangle]  
pub fn main() {
    // ...
}

The #[no_mangle] attribute tells the compiler not to mangle (rename) the function name during compilation. We need this because the Valida runtime looks for a function specifically named "main".