Rust by Example

The type statement can be used to give a new name to an existing type. Types must have UpperCamelCase names, or the compiler will raise a warning. The exception to this rule are the primitive types: usize, f32, etc.

// `NanoSecond` is a new name for `u64`.

type NanoSecond = u64;

type Inch = u64;

// Use an attribute to silence warning.

#[allow(non_camel_case_types)]

type u64_t = u64;

// TODO ^ Try removing the attribute

fn main() {

// `NanoSecond` = `Inch` = `u64_t` = `u64`.

let nanoseconds: NanoSecond = 5 as u64_t;

let inches: Inch = 2 as u64_t;

// Note that type aliases *don't* provide any extra type safety, because

// aliases are *not* new types

println!("{} nanoseconds + {} inches = {} unit?",

nanoseconds,

inches,

nanoseconds + inches);

}

הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

The main use of aliases is to reduce boilerplate; for example the IoResult type is an alias for the Result type.