Functions

# // Copyright 2023 Google LLC
# // SPDX-License-Identifier: Apache-2.0
#
fn gcd(a: u32, b: u32) -> u32 {
    if b > 0 { gcd(b, a % b) } else { a }
}

fn main() {
    dbg!(gcd(143, 52));
}

• Declaration parameters are followed by a type (the reverse of some programming languages), then a return type.
• The last expression in a function body (or any block) becomes the return value. Simply omit the ; at the end of the expression. The return keyword can be used for early return, but the "bare value" form is idiomatic at the end of a function (refactor gcd to use a return).
• Some functions have no return value, and return the 'unit type', (). The compiler will infer this if the return type is omitted.
• Overloading is not supported -- each function has a single implementation.
  • Always takes a fixed number of parameters. Default arguments are not supported. Macros can be used to support variadic functions.
  • Always takes a single set of parameter types. These types can be generic, which will be covered later.