(* Copyright (C) 2005, HELM Team.
 * 
 * This file is part of HELM, an Hypertextual, Electronic
 * Library of Mathematics, developed at the Computer Science
 * Department, University of Bologna, Italy.
 * 
 * HELM is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * HELM 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HELM; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA  02111-1307, USA.
 * 
 * For details, see the HELM World-Wide-Web page,
 * http://helm.cs.unibo.it/
 *)

open Printf

exception Parse_error of Token.flocation * string

module Level1Lexer =
struct
  type te = string * string
  let lexer = CicNotationLexer.syntax_pattern_lexer
end
module Level1Parser = Grammar.GMake (Level1Lexer)

module Level2Lexer =
struct
  type te = string * string
  let lexer = CicNotationLexer.ast_pattern_lexer
end
module Level2Parser = Grammar.GMake (Level2Lexer)

let level1_pattern = Level1Parser.Entry.create "level1_pattern"
let level2_pattern = Level2Parser.Entry.create "level2_pattern"

let return_term loc term = ()

(*let fail floc msg =*)
(*  let (x, y) = CicAst.loc_of_floc floc in*)
(*  failwith (sprintf "Error at characters %d - %d: %s" x y msg)*)

let int_of_string s =
  try
    Pervasives.int_of_string s
  with Failure _ ->
    failwith (sprintf "Lexer failure: string_of_int \"%s\" failed" s)

(* {{{ Grammar for concrete syntax patterns, notation level 1 *)
GEXTEND Level1Parser
  GLOBAL: level1_pattern;
  level1_pattern: [ [ p = pattern -> () ] ];

  pattern: [ [ p = LIST1 simple_pattern -> () ] ];

  literal: [
    [ s = SYMBOL -> ()
    | k = KEYWORD -> ()
    ]
  ];

  sep:       [ [ SYMBOL "\\SEP";      sep = literal -> () ] ];
  row_sep:   [ [ SYMBOL "\\ROWSEP";   sep = literal -> () ] ];
  field_sep: [ [ SYMBOL "\\FIELDSEP"; sep = literal -> () ] ];

  box_token: [
    [ SYMBOL "\\HBOX"; p = simple_pattern -> ()
    | SYMBOL "\\VBOX"; p = simple_pattern -> ()
    | SYMBOL "\\BREAK" -> ()
    ]
  ];

  simple_pattern:
    [ "infix" LEFTA
       (* TODO XXX many issues here:
        * - "^^" is lexed as two "^" symbols
        * - "a_b" is lexed as IDENT "a_b" *)
      [ p1 = SELF; SYMBOL "^"; p2 = SELF -> ()
      | p1 = SELF; SYMBOL "^"; SYMBOL "^"; p2 = SELF -> ()
      | p1 = SELF; SYMBOL "_"; p2 = SELF -> ()
      | p1 = SELF; SYMBOL "_"; SYMBOL "_"; p2 = SELF -> ()
      ]
    | "simple" NONA
      [ SYMBOL "\\LIST0"; p = SELF; sep = OPT sep -> ()
      | SYMBOL "\\LIST1"; p = SELF; sep = OPT sep -> ()
      | b = box_token -> ()
      | id = IDENT -> ()
      | SYMBOL "\\NUM"; id = IDENT -> ()
      | SYMBOL "\\IDENT"; id = IDENT -> ()
      | SYMBOL "\\OPT"; p = SELF -> ()
      | SYMBOL "\\ARRAY"; p = SELF; fsep = OPT field_sep; rsep = OPT row_sep ->
          ()
      | SYMBOL "\\FRAC"; p1 = SELF; p2 = SELF -> ()
      | SYMBOL "\\SQRT"; p = SELF -> ()
      | SYMBOL "\\ROOT"; p1 = SELF; SYMBOL "\\OF"; p2 = SELF ->
          ()
      | SYMBOL "["; p = pattern; SYMBOL "]" -> ()
      ]
    ];
END
(* }}} *)

(* {{{ Grammar for ast patterns, notation level 2 *)
GEXTEND Level2Parser
  GLOBAL: level2_pattern;
  level2_pattern: [ [ p = pattern -> () ] ];

  pattern: [ [ a = ast -> () ] ];

  ast: [ [ SYMBOL "\\FOO" -> () ] ];
END
(* }}} *)

let exc_located_wrapper f =
  try
    f ()
  with
  | Stdpp.Exc_located (floc, Stream.Error msg) ->
      raise (Parse_error (floc, msg))
  | Stdpp.Exc_located (floc, exn) ->
      raise (Parse_error (floc, (Printexc.to_string exn)))

let parse_syntax_pattern stream =
  exc_located_wrapper
    (fun () ->
      (Level1Parser.Entry.parse level1_pattern (Level1Parser.parsable stream)))

let parse_ast_pattern stream =
  exc_located_wrapper
    (fun () ->
      (Level2Parser.Entry.parse level2_pattern (Level2Parser.parsable stream)))

(* vim:set encoding=utf8 foldmethod=marker: *)