gm2-libs/Scan

DEFINITION MODULE Scan ;

(* Provides a primitive symbol fetching from input.
   Symbols are delimited by spaces and tabs.
   Limitation only allows one source file at
   a time to deliver symbols.  *)

EXPORT QUALIFIED GetNextSymbol, WriteError,
                 OpenSource, CloseSource,
                 TerminateOnError, DefineComments ;

(* OpenSource - opens a source file for reading.                  *)

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

(* CloseSource - closes the current source file from reading.     *)

CloseSource
PROCEDURE CloseSource ;

(* GetNextSymbol gets the next source symbol and returns it in a. *)

GetNextSymbol
PROCEDURE GetNextSymbol (VAR a: ARRAY OF CHAR) ;

(* WriteError writes a message, a, under the source line, which   *)
(* attempts to pinpoint the Symbol at fault.                      *)

WriteError
PROCEDURE WriteError (a: ARRAY OF CHAR) ;

(*
   TerminateOnError - exits with status 1 if we call WriteError.
*)

TerminateOnError
PROCEDURE TerminateOnError ;

(*
   DefineComments - defines the start of comments within the source
                    file.

                    The characters in Start define the comment start
                    and characters in End define the end.
                    The BOOLEAN eoln determine whether the comment
                    is terminated by end of line. If eoln is TRUE
                    then End is ignored.

                    If this procedure is never called then no comments
                    are allowed.
*)

DefineComments
PROCEDURE DefineComments (Start, End: ARRAY OF CHAR; eoln: BOOLEAN) ;

END Scan.