Macro message 

macro_rules! message {
    ($($arg:tt)*) => { ... };
}

Emit an R message from Rust with rust_message class layering.

Requires error_in_r mode (the default for #[miniextendr] functions). The raised condition has class c("rust_message", "simpleMessage", "message", "condition"). Muffled by suppressMessages() automatically (standard R restart mechanism).

Example

use miniextendr_api::message;

#[miniextendr]
fn log_step(step: i32) {
    message!("step {} complete", step);
}

log_step(3L)
# step 3 complete

suppressMessages(log_step(3L))  # no output