ocaml-non-empty-list

A list that is known, statically, to be nonempty. The hd and tl functions don't require option types, or exceptions, improving safety.

This library follows closely Janestreet's Base library, providing similar complexity and functions to Base.List.

Usage

open Non_empty_list;;

let one = [1];;
val one : int non_empty_list = (::) (1, []) (* [1] *)

let two = cons 2 one;;
val two : int non_empty_list = (::) (2, [1]) (* [2; 1] *)

hd one;;
- : int = 1

append one two;;
- : int non_empty_list = (::) (1, [2; 1]) (* [1; 2; 1] *)

length two;;
- : int = 2

to_list two;;
- : int list = [2; 1]

mem ~equal:( = ) two 2;;
- : bool = true

reduce ~f:( + ) two;;
- : int = 3

Testing

dune build
dune runtest