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(* PushBackInput.def provides a method for pushing back and consuming input.
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.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. *)
DEFINITION MODULE PushBackInput ;
FROM FIO IMPORT File ;
FROM DynamicStrings IMPORT String ;
EXPORT QUALIFIED Open, PutCh, GetCh, Error, WarnError, WarnString,
Close, SetDebug, GetExitStatus, PutStr,
PutString, GetColumnPosition, GetCurrentLine ;
(*
Open - opens a file for reading.
*)
PROCEDURE Open (a: ARRAY OF CHAR) : File ;
(*
GetCh - gets a character from either the push back stack or
from file, f.
*)
PROCEDURE GetCh (f: File) : CHAR ;
(*
PutCh - pushes a character onto the push back stack, it also
returns the character which has been pushed.
*)
PROCEDURE PutCh (ch: CHAR) : CHAR ;
(*
PutString - pushes a string onto the push back stack.
*)
PROCEDURE PutString (a: ARRAY OF CHAR) ;
(*
PutStr - pushes a dynamic string onto the push back stack.
The string, s, is not deallocated.
*)
PROCEDURE PutStr (s: String) ;
(*
Error - emits an error message with the appropriate file, line combination.
*)
PROCEDURE Error (a: ARRAY OF CHAR) ;
(*
WarnError - emits an error message with the appropriate file, line combination.
It does not terminate but when the program finishes an exit status of
1 will be issued.
*)
PROCEDURE WarnError (a: ARRAY OF CHAR) ;
(*
WarnString - emits an error message with the appropriate file, line combination.
It does not terminate but when the program finishes an exit status of
1 will be issued.
*)
PROCEDURE WarnString (s: String) ;
(*
Close - closes the opened file.
*)
PROCEDURE Close (f: File) ;
(*
GetExitStatus - returns the exit status which will be 1 if any warnings were issued.
*)
PROCEDURE GetExitStatus () : CARDINAL ;
(*
SetDebug - sets the debug flag on or off.
*)
PROCEDURE SetDebug (d: BOOLEAN) ;
(*
GetColumnPosition - returns the column position of the current character.
*)
PROCEDURE GetColumnPosition () : CARDINAL ;
(*
GetCurrentLine - returns the current line number.
*)
PROCEDURE GetCurrentLine () : CARDINAL ;
END PushBackInput.
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