external_arg_spec.ml

(* Copyright (C) 2015 - 2016 Bloomberg Finance L.P.
 * Copyright (C) 2017 - Hongbo Zhang, Authors of ReScript
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * In addition to the permissions granted to you by the LGPL, you may combine
 * or link a "work that uses the Library" with a publicly distributed version
 * of this file to produce a combined library or application, then distribute
 * that combined work under the terms of your choosing, with no requirement
 * to comply with the obligations normally placed on you by section 4 of the
 * LGPL version 3 (or the corresponding section of a later version of the LGPL
 * should you choose to use a later version).
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *)

(** type definitions for arguments to a function declared external *)

type delim = | DNone | DStarJ | DJson

type cst =
  | Arg_int_lit of int
  | Arg_string_lit of string * delim

type label_noname = Arg_label | Arg_empty | Arg_optional

type label =
  | Obj_empty
  | Obj_label of { name : string }
  | Obj_optional of { name : string; for_sure_no_nested_option : bool }

(* it will be ignored , side effect will be recorded *)

(* This type is used to give some meta info on each argument *)
type attr =
  | Poly_var_string of {
      descr : (string * string) list;
          (* introduced by attributes @string
             and @as
          *)
    }
  | Poly_var of {
      descr : (string * string) list option;
          (* introduced by attributes @string
             and @as
          *)
    }
  (* `a does not have any value*)
  | Int of (string * int) list (* ([`a | `b ] [@int])*)
  | Arg_cst of cst
  | Fn_uncurry_arity of int (* annotated with [@uncurry ] or [@uncurry 2]*)
  (* maybe we can improve it as a combination of {!Asttypes.constant} and tuple *)
  | Extern_unit
  | Nothing
  | Ignore
  | Unwrap

type param = { arg_type : attr; arg_label : label_noname }

type obj_param = { obj_arg_type : attr; obj_arg_label : label }

type obj_params = obj_param list

type params = param list

let cst_int i = Arg_int_lit i

let cst_string s delim = Arg_string_lit (s, delim)

let empty_label = Obj_empty

let obj_label name = Obj_label { name }

let optional for_sure_no_nested_option name =
  Obj_optional { name; for_sure_no_nested_option }

let empty_kind obj_arg_type = { obj_arg_label = empty_label; obj_arg_type }

let dummy = { arg_type = Nothing; arg_label = Arg_empty }