lib.rs

use smart_contract::log;
use smart_contract_macros::smart_contract;
use smart_contract::payload::Parameters;

// The contract will store an instance of the same Universe struct implemented in the tutorial
// we also have a "stepped" construct that checks whether someone has already stepped the contract in a given consensus round
struct Contract {
    universe: Universe,
    stepped: [u8; 32],
}

#[smart_contract]
impl Contract {
    pub fn init(_params: &mut Parameters) -> Self {
        Self {
            universe: Universe::new(),
            stepped: [0; 32],
        }
    }

    pub fn step(&mut self, params: &mut Parameters) -> Result<(), String> {
        // only step once per round
        if self.stepped == params.round_id {
            return Ok(())
        }
        self.stepped = params.round_id;
        self.universe.tick();
        Ok(())
    }

    pub fn render(&mut self, _params: &mut Parameters) -> Result<(), String> {
        log(&self.universe.render());
        Ok(())
    }
}

// ... the rest of the code in the Rust Wasm tutorial https://rustwasm.github.io/docs/book/game-of-life/implementing.html#rust-implementation