Libraries and executables with dune

I’ve produced a project structure using:

dune init proj lichessocaml

I wrote the code in bin/ and made sure it worked in principle on the REPL. Now, I’m trying to separate the functional code into a library used by main.

I’ve added “open Mylibrary” to the top of main – which the compiler doesn’t complain about, however main can’t seem to see the types declared in the library.

THE QUESTION: what do I need to do for main to be able to see inside the library? Ideally I would expose just the types and the to_* functions from the code below:

module StringMap = Map.Make(String)

type outcome_enum = WhiteWin | BlackWin | Draw
type interval = { mins: int; inc: int }
type game = {
    utc_date: string;
    time_control: interval;
    termination: string;
    white: string;
    black: string;
    white_elo: int;
    black_elo: int;
    result: outcome_enum;
    site: string;
    event: string;
    opening: string;
    eco: string;
    game: string;

let to_pairs x =
  let re = Re2.create_exn "([A-Za-z]+) \"([^\"]+)" in
    let match_ = Re2.first_match_exn re x in
    let k = Re2.Match.get match_ ~sub:(`Index 1) in
    let v = Re2.Match.get match_ ~sub:(`Index 2) in
    Some ((Option.value k ~default:""),(Option.value v ~default:""))
    _ -> let re = Re2.create_exn "^(.+)$" in
         try Some ("Game", (Re2.find_first_exn re x))
         with _ -> None

let rec to_map ?(m=StringMap.empty) f =
  match f () with
  | None -> to_map ~m:m f
  | Some ("Game" as k,v) -> Some (StringMap.add k v m)
  | Some (k,v) -> to_map ~m:(StringMap.add k v m) f

let get_interval x =
    let re = Re2.create_exn "([0-9]+)\\+([0-9]+)" in
    let match_ = Re2.first_match_exn re x in
    let mins = Re2.Match.get match_ ~sub:(`Index 1) in
    let inc = Re2.Match.get match_ ~sub:(`Index 2) in
    { mins=int_of_string (Option.value mins ~default:"0");
      inc=int_of_string (Option.value inc ~default:"0")}
  with _ -> {mins=0; inc=0}

let get_result x =
  match x with
  | "1-0" -> WhiteWin
  | "0-1" -> BlackWin
  | _     -> Draw

let get_int x =
  int_of_string x
let to_record m =
  match m with
  | None -> None
  | Some m -> (
    let f k= StringMap.find k m in
    Some {
        event=f "Event";
        white=f "White";
        black=f "Black";
        utc_date=f "UTCDate";
        time_control=get_interval (f "TimeControl");
        termination=f "Termination";
        white_elo=get_int (f "WhiteElo");
        black_elo=get_int (f "BlackElo");
        result=get_result (f "Result");
        site=f "Site";
        opening=f "Opening";
        eco=f "ECO";
        game=f "Game";

I’ve figured out the issue. So if you do a “dune build” in the lib/ directory separately, and then try to do a build from project root, it looks like the two interfere with each other. Once I deleted the build_ from the lib/ directory , everything seem to work ok.