Code shared from the Rust Playground

playground.rs

...

#[derive(Serialize, Deserialize)]
pub enum Msg {
    Hello,
    Greet { name: String },
}

[entry_point]
pub fn execute(
    deps: DepsMut,
    _env: Env,
    _info: MessageInfo,
    msg: Msg,
) -> Result<Response, ContractError> {
    match msg {
        Msg::Hello => println!("hello world!"),
        Msg::Greet { name } => println!("hello, {}", &name),
    }
    ...
}