traits.rs

struct bar;

impl Bar () {
  new () -> Self {
    Bar{}
  }
}

impl Writer for Bar {
  // this will only ever be called by the public-facing "write" method.
  // the question is: what should we name this method? Right now the name conflicts
  // with the public-facing API.
  write (&self) {
  }
}

trait Writer {
  // this one is public facing
  write (&self) {
    println!("prepping write");
    self.bar(); // calls the interal API
    println!("done with write");
  }
}

fn main () {
  let bar = Bar::new()
  bar.write() // calls the public API
}