Hello World

Using the console! macro from the stylus_sdk allows you to print output to the terminal for debugging purposes. To view the output, you'll need to run a local Stylus dev node as described in the Arbitrum docs and set the debug feature flag as shown in line 7 of the Cargo.toml file below.

The console! macro works similar to the built-in println! macro that comes with Rust.

Examples

// Out: Stylus says: 'hello there!'
console!("hello there!");
// Out: Stylus says: 'format some arguments'
console!("format {} arguments", "some");

let local_variable = "Stylus";
// Out: Stylus says: 'Stylus is awesome!'
console!("{local_variable} is awesome!");
// Out: Stylus says: 'When will you try out Stylus?'
console!("When will you try out {}?", local_variable);

src/main.rs

#![cfg_attr(not(feature = "export-abi"), no_main)]

extern crate alloc;


use stylus_sdk::{console, prelude::*, stylus_proc::entrypoint, ArbResult};

#[storage]
#[entrypoint]
pub struct Hello;


#[public]
impl Hello {
    fn user_main(_input: Vec<u8>) -> ArbResult {
        // Will print 'Stylus says: Hello Stylus!' on your local dev node
        // Be sure to add "debug" feature flag to your Cargo.toml file as
        // shown below.
        console!("Hello Stylus!");
        Ok(Vec::new())
    }
}

Cargo.toml

[package]
name = "stylus_hello_world"
version = "0.1.7"
edition = "2021"
license = "MIT OR Apache-2.0"
keywords = ["arbitrum", "ethereum", "stylus", "alloy"]

[dependencies]
alloy-primitives = "=0.7.6"
alloy-sol-types = "=0.7.6"
mini-alloc = "0.4.2"
stylus-sdk = "0.6.0"
hex = "0.4.3"
sha3 = "0.10"

[dev-dependencies]
tokio = { version = "1.12.0", features = ["full"] }
ethers = "2.0"
eyre = "0.6.8"

[features]
export-abi = ["stylus-sdk/export-abi"]

[lib]
crate-type = ["lib", "cdylib"]

[profile.release]
codegen-units = 1
strip = true
lto = true
panic = "abort"
opt-level = "s"