(* M2Lex.def provides a non tokenised lexical analyser.

Copyright (C) 2001-2023 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.

This file is part of GNU Modula-2.

GNU Modula-2 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 3, or (at your option)
any later version.

GNU Modula-2 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 GNU Modula-2; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  *)
DEFINITION MODULE M2Lex ;

(*
   Title      : M2Lex
   Author     : Gaius Mulley
   Date       : Date: Sat 16-09-1989 Time: 17:54:22.58
   LastEdit   : Date: Sat 16-09-1989 Time: 17:54:22.58
   System     : UNIX (GNU Modula-2)
   Description: Provides a non tokenised version of M2Lexical.
                Symbols are distinct MODULA-2 symbols.
*)

EXPORT QUALIFIED MaxLine,
                 GetSymbol,
                 PutSymbol,
                 CurrentSymbol,
                 LastSymbol,
                 OpenSource,
                 CloseSource,
                 SymIs,
                 IsSym,
                 WriteError ;

CONST
   MaxLine = 1024 ;

VAR
   LastSymbol,
   CurrentSymbol : ARRAY [0..MaxLine] OF CHAR ;


(*
   OpenSource - Attempts to open the source file, a.
                The success of the operation is returned.
*)

PROCEDURE OpenSource (a: ARRAY OF CHAR) : BOOLEAN ;


(*
   CloseSource - Closes the current open file.
*)

PROCEDURE CloseSource ;


(*
   SymIs - if Name is equal to the CurrentSymbol the next Symbol is read
           and true is returned, otherwise false is returned.
*)

PROCEDURE SymIs (Name: ARRAY OF CHAR) : BOOLEAN ;


(*
   IsSym - returns the result of the comparison between CurrentSymbol
           and Name.
*)

PROCEDURE IsSym (Name: ARRAY OF CHAR) : BOOLEAN ;


(*
   GetSymbol - gets the next Symbol into CurrentSymbol.
*)

PROCEDURE GetSymbol ;


(*
   PutSymbol - pushes a symbol, Name, back onto the input.
               GetSymbol will set CurrentSymbol to, Name.
*)

PROCEDURE PutSymbol (Name: ARRAY OF CHAR) ;


(*
   WriteError - displays the source line and points to the symbol in error.
                The message, a, is displayed.
*)

PROCEDURE WriteError (a: ARRAY OF CHAR) ;


END M2Lex.
