Lists

List<A> is a homogeneous linked list. [head | tail] conses; [] is the empty list. Recursive functions are ordinary functions: all signatures in a module are collected before bodies are checked.

module lists

pub fn prepend(head: Integer, tail: List<Integer>) -> List<Integer> {
  [head | tail]
}

pub fn sum(items: List<Integer>) -> Integer {
  match items {
    [] -> 0
    [head | tail] -> head + sum(tail)
  }
}