let load' : string -> (ImportConf.Syntax.t, string) Result.t =
 fun content -> Otoml.Parser.from_string content |> ImportConf.t_of_toml

(** Read the configuration in toml and return the internal representation *)
let load : string -> ImportConf.Syntax.t =
 fun content -> Result.get_ok (load' content)

let conf =
  load
    {|[source]
  file = "source.xlsx"
  name = "source"

[externals.other]
  intern_key = ":A"
  file = "other.xlsx"
  extern_key = ":C"
  allow_missing = false

[externals.last_file]
  intern_key = ":other.A"
  file = "last.xlsx"
  extern_key = ":C"
  allow_missing = true 

[sheet]
  columns = [
    ":A ^ '_'",
   ":B", 
   ":last_file.E", 
  ]|}

let external_table_source =
  ImportDataTypes.Table.{ file = "source.xlsx"; tab = 1; name = "source" }

let external_table_other =
  ImportDataTypes.Table.{ file = "other.xlsx"; tab = 1; name = "other" }

let external_other =
  ImportConf.Syntax.Extern.
    {
      intern_key = Path { alias = None; column = 1 };
      target = external_table_other;
      extern_key = Path 3;
      allow_missing = false;
      match_rule = None;
    }

let external_table_last =
  ImportDataTypes.Table.{ file = "last.xlsx"; tab = 1; name = "last_file" }

let external_last =
  ImportConf.Syntax.Extern.
    {
      intern_key = Path { alias = Some "other"; column = 1 };
      target = external_table_last;
      extern_key = Path 3;
      allow_missing = true;
      match_rule = None;
    }