(* M2LexBuf.def provides a buffer for m2.flex.

Copyright (C) 2001-2025 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 M2LexBuf ;

(*
    Title      : M2LexBuf
    Author     : Gaius Mulley
    System     : UNIX (GNU Modula-2)
    Date       : Fri Jul 27 12:42:13 2001
    Description: provides a buffer for the all the tokens created by m2.lex.
*)

FROM SYSTEM IMPORT ADDRESS ;
FROM M2Reserved IMPORT toktype ;
FROM DynamicStrings IMPORT String ;
FROM gcctypes IMPORT location_t ;
FROM NameKey IMPORT Name ;


CONST
   UnknownTokenNo = 0 ;
   BuiltinTokenNo = 1 ;

VAR
   currenttoken  : toktype ;
   currentstring : ADDRESS ;
   currentcolumn : CARDINAL ;
   currentinteger: INTEGER ;


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

PROCEDURE OpenSource (s: String) : BOOLEAN ;


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

PROCEDURE CloseSource ;


(*
   ReInitialize - re-initialize the all the data structures.
*)

PROCEDURE ReInitialize ;


(*
   ResetForNewPass - reset the buffer pointers to the beginning ready for
                     a new pass
*)

PROCEDURE ResetForNewPass ;


(*
   GetToken - gets the next token into currenttoken.
*)

PROCEDURE GetToken ;


(*
   InsertToken - inserts a symbol, token, infront of the current token
                 ready for the next pass.
*)

PROCEDURE InsertToken (token: toktype) ;


(*
   InsertTokenAndRewind - inserts a symbol, token, infront of the current token
                          and then moves the token stream back onto the inserted token.
*)

PROCEDURE InsertTokenAndRewind (token: toktype) ;


(*
   GetPreviousTokenLineNo - returns the line number of the previous token.
*)

PROCEDURE GetPreviousTokenLineNo () : CARDINAL ;


(*
   GetLineNo - returns the current line number where the symbol occurs in
               the source file.
*)

PROCEDURE GetLineNo () : CARDINAL ;


(*
   GetTokenNo - returns the current token number.
*)

PROCEDURE GetTokenNo () : CARDINAL ;


(*
   GetTokenName - returns the token name given the tokenno.
*)

PROCEDURE GetTokenName (tokenno: CARDINAL) : Name ;


(*
   TokenToLineNo - returns the line number of the current file for the
                   tokenno. The depth refers to the include depth.
                   A depth of 0 is the current file, depth of 1 is the file
                   which included the current file. Zero is returned if the
                   depth exceeds the file nesting level.
*)

PROCEDURE TokenToLineNo (tokenno: CARDINAL; depth: CARDINAL) : CARDINAL ;


(*
   GetColumnNo - returns the current column where the symbol occurs in
                 the source file.
*)

PROCEDURE GetColumnNo () : CARDINAL ;


(*
   TokenToColumnNo - returns the column number of the current file for the
                     tokenno. The depth refers to the include depth.
                     A depth of 0 is the current file, depth of 1 is the file
                     which included the current file. Zero is returned if the
                     depth exceeds the file nesting level.
*)

PROCEDURE TokenToColumnNo (tokenno: CARDINAL; depth: CARDINAL) : CARDINAL ;


(*
   TokenToLocation - returns the location_t corresponding to tokenno.
*)

PROCEDURE TokenToLocation (tokenno: CARDINAL) : location_t ;


(*
   FindFileNameFromToken - returns the complete FileName for the appropriate
                           source file yields the token number tokenno.
                           The, Depth, indicates the include level: 0..n
                           Level 0 is the current. NIL is returned if n+1
                           is requested.
*)

PROCEDURE FindFileNameFromToken (tokenno: CARDINAL; depth: CARDINAL) : String ;


(*
   GetFileName - returns a String defining the current file.
*)

PROCEDURE GetFileName () : String ;


(*
   MakeVirtualTok - providing caret, left, right are associated with a source file
                    and exist on the same src line then
                    create and return a new tokenno which is created from
                    tokenno left and right.  Otherwise return caret.
                    If caret is UnknownTokenNo then it is replaced with left or right
                    in sequence to avoid an UnknownTokenNo.
*)

PROCEDURE MakeVirtualTok (caret, left, right: CARDINAL) : CARDINAL ;


(*
   MakeVirtual2Tok - creates and return a new tokenno which is created from
                     two tokens left and right.  It tries to avoid UnknownTokenNo
                     and will fall back to left or right if necessary.
*)

PROCEDURE MakeVirtual2Tok (left, right: CARDINAL) : CARDINAL ;


(* ***********************************************************************
 *
 * These functions allow m2.lex to deliver tokens into the buffer
 *
 ************************************************************************* *)

(*
   AddTok - adds a token to the buffer.
*)

PROCEDURE AddTok (t: toktype) ;


(*
   AddTokCharStar - adds a token to the buffer and an additional string, s.
                    A copy of string, s, is made.
*)

PROCEDURE AddTokCharStar (t: toktype; s: ADDRESS) ;


(*
   AddTokInteger - adds a token and an integer to the buffer.
*)

PROCEDURE AddTokInteger (t: toktype; i: INTEGER) ;


(*
   SetFile - sets the current filename to, filename.
*)

PROCEDURE SetFile (filename: ADDRESS) ;


(*
   PushFile - indicates that, filename, has just been included.
*)

PROCEDURE PushFile (filename: ADDRESS) ;


(*
   PopFile - indicates that we are returning to, filename, having finished
             an include.
*)

PROCEDURE PopFile (filename: ADDRESS) ;


(*
   PrintTokenNo - displays token and the location of the token.
*)

PROCEDURE PrintTokenNo (tokenno: CARDINAL) ;


(*
   DisplayToken - display the token name using printf0 no newline is emitted.
*)

PROCEDURE DisplayToken (tok: toktype) ;


(*
   DumpTokens - displays all tokens.
*)

PROCEDURE DumpTokens ;


END M2LexBuf.