gm2-libs/RTExceptions

DEFINITION MODULE RTExceptions ;

(* Runtime exception handler routines.  This should
   be considered as a system module for GNU Modula-2
   and allow the compiler to interface with exception
   handling.  *)

FROM SYSTEM IMPORT ADDRESS ;
EXPORT QUALIFIED EHBlock,
                 Raise, SetExceptionBlock, GetExceptionBlock,
                 GetTextBuffer, GetTextBufferSize, GetNumber,
                 InitExceptionBlock, KillExceptionBlock,
                 PushHandler, PopHandler,
                 BaseExceptionsThrow, DefaultErrorCatch,
                 IsInExceptionState, SetExceptionState,
                 SwitchExceptionState, GetBaseExceptionBlock,
                 SetExceptionSource, GetExceptionSource ;

TYPE
EHBlock (type)
   EHBlock ;
ProcedureHandler (type)
   ProcedureHandler = PROCEDURE ;

(*
   Raise - invoke the exception handler associated with, number,
           in the active EHBlock.  It keeps a record of the number
           and message in the EHBlock for later use.
*)

Raise
PROCEDURE Raise (number: CARDINAL;
                 file: ADDRESS; line: CARDINAL;
                 column: CARDINAL; function: ADDRESS;
                 message: ADDRESS) ;

(*
   SetExceptionBlock - sets, source, as the active EHB.
*)

SetExceptionBlock
PROCEDURE SetExceptionBlock (source: EHBlock) ;

(*
   GetExceptionBlock - returns the active EHB.
*)

GetExceptionBlock
PROCEDURE GetExceptionBlock () : EHBlock ;

(*
   GetTextBuffer - returns the address of the EHB buffer.
*)

GetTextBuffer
PROCEDURE GetTextBuffer (e: EHBlock) : ADDRESS ;

(*
   GetTextBufferSize - return the size of the EHB text buffer.
*)

GetTextBufferSize
PROCEDURE GetTextBufferSize (e: EHBlock) : CARDINAL ;

(*
   GetNumber - return the exception number associated with,
               source.
*)

GetNumber
PROCEDURE GetNumber (source: EHBlock) : CARDINAL ;

(*
   InitExceptionBlock - creates and returns a new exception block.
*)

InitExceptionBlock
PROCEDURE InitExceptionBlock () : EHBlock ;

(*
   KillExceptionBlock - destroys the EHB, e, and all its handlers.
*)

KillExceptionBlock
PROCEDURE KillExceptionBlock (e: EHBlock) : EHBlock ;

(*
   PushHandler - install a handler in EHB, e.
*)

PushHandler
PROCEDURE PushHandler (e: EHBlock; number: CARDINAL; p: ProcedureHandler) ;

(*
   PopHandler - removes the handler associated with, number, from
                EHB, e.
*)

PopHandler
PROCEDURE PopHandler (e: EHBlock; number: CARDINAL) ;

(*
   DefaultErrorCatch - displays the current error message in
                       the current exception block and then
                       calls HALT.
*)

DefaultErrorCatch
PROCEDURE DefaultErrorCatch ;

(*
   BaseExceptionsThrow - configures the Modula-2 exceptions to call
                         THROW which in turn can be caught by an
                         exception block.  If this is not called then
                         a Modula-2 exception will simply call an
                         error message routine and then HALT.
*)

BaseExceptionsThrow
PROCEDURE BaseExceptionsThrow ;

(*
   IsInExceptionState - returns TRUE if the program is currently
                        in the exception state.
*)

IsInExceptionState
PROCEDURE IsInExceptionState () : BOOLEAN ;

(*
   SetExceptionState - returns the current exception state and
                       then sets the current exception state to,
                       to.
*)

SetExceptionState
PROCEDURE SetExceptionState (to: BOOLEAN) : BOOLEAN ;

(*
   SwitchExceptionState - assigns, from, with the current exception
                          state and then assigns the current exception
                          to, to.
*)

SwitchExceptionState
PROCEDURE SwitchExceptionState (VAR from: BOOLEAN; to: BOOLEAN) ;

(*
   GetBaseExceptionBlock - returns the initial language exception block
                           created.
*)

GetBaseExceptionBlock
PROCEDURE GetBaseExceptionBlock () : EHBlock ;

(*
   SetExceptionSource - sets the current exception source to, source.
*)

SetExceptionSource
PROCEDURE SetExceptionSource (source: ADDRESS) ;

(*
   GetExceptionSource - returns the current exception source.
*)

GetExceptionSource
PROCEDURE GetExceptionSource () : ADDRESS ;

END RTExceptions.