GriffinKernel.mesa
Copyright © 1985 by Xerox Corporation. All rights reserved.
Last Edited by: Ken Pier, October 18, 1985 11:07:16 am PDT
GriffinKernel:
CEDAR
DEFINITIONS =
BEGIN
Data: TYPE = REF DataRec;
DataRec:
TYPE;
-- opaque type defined in GriffinData. One DataRec exists per viewer. You need to do this "opaque" to get rid of compilation dependencies; interfaces can reference GriffinKernel.Data and their implementations can bind to the concrete type in GriffinData. GriffinData can, in turn, reference objects in other interfaces that can be compiled earlier. Any implementation module that wishes to go inside a DataRec will EXPORT a public type to this interface. For example:
MumbleImpl: .... EXPORTS Mumble, GriffinKernel ...
Data: TYPE = REF DataRec;
DataRec: PUBLIC TYPE = GriffinData.DataRec; --exported to GriffinKernel. This ties the concrete representation in GriffinData to the opaque type in GriffinKernel.
ClipBox: TYPE = REF Box;
Box: TYPE = RECORD [enable: BOOL ← FALSE, x, y, w, h: INT] -- from Display, kept in Data