ocaml-community/ocaml-linenoise

Self-contained OCaml bindings to linenoise, easy high level readline functionality in OCaml

Linenoise in OCaml

Benefits

1. BSD licensed.
2. No system dependencies, no need for readline on your machine.
3. Related to 2, these bindings are self-contained, the source for linenoise is in this repo and compiled all together with the OCaml.
4. Written in OCaml + C.
5. Pretty cool hints feature, see the gif.
6. Additional features compared to linenoise, such as history search

Installation

It is easy with opam

$ opam install linenoise

See the pretty documentation here

Example code

This example is also included in the repo under examples:

let rec user_input prompt cb =
  match LNoise.linenoise prompt with
  | None -> ()
  | Some v ->
    cb v;
    user_input prompt cb

let () =
  (* LNoise.set_multiline true; *)
  LNoise.set_hints_callback (fun line ->
      if line <> "git remote add " then None
      else Some (" <this is the remote name> <this is the remote URL>",
                 LNoise.Yellow,
                 true)
    );
  LNoise.history_load ~filename:"history.txt" |> ignore;
  LNoise.history_set ~max_length:100 |> ignore;
  LNoise.set_completion_callback begin fun line_so_far ln_completions ->
    if line_so_far <> "" && line_so_far.[0] = 'h' then
      ["Hey"; "Howard"; "Hughes";"Hocus"]
      |> List.iter (LNoise.add_completion ln_completions);
  end;
  ["These are OCaml bindings to linenoise";
   "get tab completion with <TAB>, type h then hit <TAB>";
   "type quit to exit gracefully";
   "By Edgar Aroutiounian\n"]
  |> List.iter print_endline;
  (fun from_user ->
     if from_user = "quit" then exit 0;
     LNoise.history_add from_user |> ignore;
     LNoise.history_save ~filename:"history.txt" |> ignore;
     Printf.sprintf "Got: %s" from_user |> print_endline
  )
  |> user_input "test_program> "