path: root/meap/meap-code/ch3/ch3-defining-files-neatly.rs

#[derive(Debug)]
struct File {
  name: String,
  data: Vec<u8>,
}

impl File {
  fn new(name: &str) -> File { // <1> As `File::new()` is a completely normal function--rather than something blessed by the language--we need to tell Rust that it will be returning a `File` from this function
    File {                      // <2>
      name: String::from(name), // <2> `File::new()` does little more than encapsulate the object creation syntax 
      data: Vec::new(),         // <2>
    }
  }
  
  // fn len(&self) -> usize {  // <3> `File::len()` takes an implicit argument `self`. You'll notice that there is no explicit argument provided on line 25. 
  //   self.data.len() // <4> `usize` is the type returned by `Vec<T>::len()`, which is sent directly through to the caller
  // }
}

fn main() {
  let f3 = File::new("f3.txt");
  
  let f3_name = &f3.name; // <5> Fields are private by default, but can be accessed within the module that defines the struct. The module system is discussed further on in the chapter. 
 //let f3_length = f3.len();
 let f3_length = f3.data.len();
  
  println!("{:?}", f3);
  println!("{} is {} bytes long", f3_name, f3_length);
}