(* camlp4r *)
(***********************************************************************)
(*                                                                     *)
(*                             Camlp4                                  *)
(*                                                                     *)
(*        Daniel de Rauglaudre, projet Cristal, INRIA Rocquencourt     *)
(*                                                                     *)
(*  Copyright 2001 Institut National de Recherche en Informatique et   *)
(*  Automatique.  Distributed only by permission.                      *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

type t = (string * string);
type pattern = (string * string);

exception Error of string;

value make_loc (bp, ep) =
   ({ (Lexing.dummy_pos) with Lexing.pos_cnum = bp; Lexing.pos_lnum = 1 },
    { (Lexing.dummy_pos) with Lexing.pos_cnum = ep; Lexing.pos_lnum = 1 })
;

value nowhere = { (Lexing.dummy_pos) with Lexing.pos_cnum = 0 };

value dummy_loc = (Lexing.dummy_pos, Lexing.dummy_pos);

value succ_pos p =
    { ( p ) with Lexing.pos_cnum = p.Lexing.pos_cnum + 1};
value lt_pos p1 p2 = p1.Lexing.pos_cnum < p2.Lexing.pos_cnum;

type flocation = (Lexing.position * Lexing.position);

type flocation_function = int -> flocation;
type lexer_func 'te = Stream.t char -> (Stream.t 'te * flocation_function);

type glexer 'te =
  { tok_func : lexer_func 'te;
    tok_using : pattern -> unit;
    tok_removing : pattern -> unit;
    tok_match : pattern -> 'te -> string;
    tok_text : pattern -> string;
    tok_comm : mutable option (list flocation) }
;
type lexer =
  { func : lexer_func t;
    using : pattern -> unit;
    removing : pattern -> unit;
    tparse : pattern -> option (Stream.t t -> string);
    text : pattern -> string }
;

value lexer_text (con, prm) =
  if con = "" then "'" ^ prm ^ "'"
  else if prm = "" then con
  else con ^ " '" ^ prm ^ "'"
;

value locerr () = invalid_arg "Lexer: flocation function";
value loct_create () = (ref (Array.create 1024 None), ref False);
value loct_func (loct, ov) i =
  match
    if i < 0 || i >= Array.length loct.val then
      if ov.val then Some (nowhere, nowhere) else None
    else Array.unsafe_get loct.val i
  with
  [ Some loc -> loc
  | _ -> locerr () ]
;
value loct_add (loct, ov) i loc =
  if i >= Array.length loct.val then
    let new_tmax = Array.length loct.val * 2 in
    if new_tmax < Sys.max_array_length then do {
      let new_loct = Array.create new_tmax None in
      Array.blit loct.val 0 new_loct 0 (Array.length loct.val);
      loct.val := new_loct;
      loct.val.(i) := Some loc
    }
    else ov.val := True
  else loct.val.(i) := Some loc
;

value make_stream_and_flocation next_token_loc =
  let loct = loct_create () in
  let ts =
    Stream.from
      (fun i ->
         let (tok, loc) = next_token_loc () in
         do { loct_add loct i loc; Some tok })
  in
  (ts, loct_func loct)
;

value lexer_func_of_parser next_token_loc cs =
  make_stream_and_flocation (fun () -> next_token_loc cs)
;

value lexer_func_of_ocamllex lexfun cs =
  let lb =
    Lexing.from_function
      (fun s n ->
         try do { s.[0] := Stream.next cs; 1 } with [ Stream.Failure -> 0 ])
  in
  let next_token_loc _ =
    let tok = lexfun lb in
    let loc = (Lexing.lexeme_start_p lb, Lexing.lexeme_end_p lb) in
    (tok, loc)
  in
  make_stream_and_flocation next_token_loc
;

(* Char and string tokens to real chars and string *)

value buff = ref (String.create 80);
value store len x =
  do {
    if len >= String.length buff.val then
      buff.val := buff.val ^ String.create (String.length buff.val)
    else ();
    buff.val.[len] := x;
    succ len
  }
;
value mstore len s =
  add_rec len 0 where rec add_rec len i =
    if i == String.length s then len else add_rec (store len s.[i]) (succ i)
;
value get_buff len = String.sub buff.val 0 len;

value valch x = Char.code x - Char.code '0';
value valch_a x = Char.code x - Char.code 'a' + 10;
value valch_A x = Char.code x - Char.code 'A' + 10;

value rec backslash s i =
  if i = String.length s then raise Not_found
  else
    match s.[i] with
    [ 'n' -> ('\n', i + 1)
    | 'r' -> ('\r', i + 1)
    | 't' -> ('\t', i + 1)
    | 'b' -> ('\b', i + 1)
    | '\\' -> ('\\', i + 1)
    | '"' -> ('"', i + 1)
    | ''' -> (''', i + 1)
    | '0'..'9' as c -> backslash1 (valch c) s (i + 1)
    | 'x' -> backslash1h s (i + 1)
    | _ -> raise Not_found ]
and backslash1 cod s i =
  if i = String.length s then raise Not_found
  else
    match s.[i] with
    [ '0'..'9' as c -> backslash2 (10 * cod + valch c) s (i + 1)
    | _ -> raise Not_found ]
and backslash2 cod s i =
  if i = String.length s then raise Not_found
  else
    match s.[i] with
    [ '0'..'9' as c -> (Char.chr (10 * cod + valch c), i + 1)
    | _ -> raise Not_found ]
and backslash1h s i =
  if i = String.length s then raise Not_found
  else
    match s.[i] with
    [ '0'..'9' as c -> backslash2h (valch c) s (i + 1)
    | 'a'..'f' as c -> backslash2h (valch_a c) s (i + 1)
    | 'A'..'F' as c -> backslash2h (valch_A c) s (i + 1)
    | _ -> raise Not_found ]
and backslash2h cod s i =
  if i = String.length s then ('\\', i - 2)
  else
    match s.[i] with
    [ '0'..'9' as c -> (Char.chr (16 * cod + valch c), i + 1)
    | 'a'..'f' as c -> (Char.chr (16 * cod + valch_a c), i + 1)
    | 'A'..'F' as c -> (Char.chr (16 * cod + valch_A c), i + 1)
    | _ -> raise Not_found ]
;

value rec skip_indent s i =
  if i = String.length s then i
  else
    match s.[i] with
    [ ' ' | '\t' -> skip_indent s (i + 1)
    | _ -> i ]
;

value skip_opt_linefeed s i =
  if i = String.length s then i else if s.[i] = '\010' then i + 1 else i
;

value eval_char s =
  if String.length s = 1 then s.[0]
  else if String.length s = 0 then failwith "invalid char token"
  else if s.[0] = '\\' then
    if String.length s = 2 && s.[1] = ''' then '''
    else
      try
        let (c, i) = backslash s 1 in
        if i = String.length s then c else raise Not_found
      with
      [ Not_found -> failwith "invalid char token" ]
  else failwith "invalid char token"
;

value eval_string  (bp, ep) s =
  loop 0 0 where rec loop len i =
    if i = String.length s then get_buff len
    else
      let (len, i) =
        if s.[i] = '\\' then
          let i = i + 1 in
          if i = String.length s then failwith "invalid string token"
          else if s.[i] = '"' then (store len '"', i + 1)
          else
            match s.[i] with
            [ '\010' -> (len, skip_indent s (i + 1))
            | '\013' -> (len, skip_indent s (skip_opt_linefeed s (i + 1)))
            | c ->
                try
                  let (c, i) = backslash s i in
                  (store len c, i)
                with
                [ Not_found -> do {
                    Printf.eprintf
                     "Warning: char %d, Invalid backslash escape in string\n%!"
                     (bp.Lexing.pos_cnum + i + 1);
                    (store (store len '\\') c, i + 1) } ] ]
        else (store len s.[i], i + 1)
      in
      loop len i
;

value default_match =
  fun
  [ ("ANY", "") -> fun (con, prm) -> prm
  | ("ANY", v) ->
      fun (con, prm) -> if v = prm then v else raise Stream.Failure
  | (p_con, "") ->
      fun (con, prm) -> if con = p_con then prm else raise Stream.Failure
  | (p_con, p_prm) ->
      fun (con, prm) ->
        if con = p_con && prm = p_prm then prm else raise Stream.Failure ]
;