type code_pos = { line : int; col : int }
type lexer_error = { pos : code_pos; msg : string }

module LexerError = struct
  type t = lexer_error

  let make (pos : code_pos) (msg : string) : lexer_error =
    (* let pos = { line; col } in *)
    { pos; msg }

  let print (e : lexer_error) =
    Printf.printf "LexerError at line %d, column %d: %s\n" e.pos.line e.pos.col e.msg
end

type lox_error = LexerError of lexer_error list

let print_error (e : lox_error) =
  match e with
  | LexerError es ->
      let num_errors = List.length es in
      assert (num_errors != 0);
      Printf.printf "found %d %s:\n" num_errors
        (if num_errors = 1 then "LexerError" else "LexerErrors");
      List.iter LexerError.print es

let of_lexer_error e = Result.map_error (fun e -> LexerError e) e