This module maintains the virtual
screen structures.
INTERFACEVTVirtual ; IMPORT Rd, Thread; IMPORT VTDef; TYPE T = VTDef.T; View = VTDef.View; I = VTDef.I; PROCEDURE Change (vt: T; begin, oEnd, nEnd: I) RAISES {Rd.EndOfFile, Rd.Failure, Thread.Alerted}; PROCEDURE SetStart (view : View; from : I; n : CARDINAL := 0; force: BOOLEAN := FALSE) RAISES {Rd.EndOfFile, Rd.Failure, Thread.Alerted}; PROCEDURE Update (vt: T) RAISES {Rd.EndOfFile, Rd.Failure, Thread.Alerted}; PROCEDURE UpdateView (view: View) RAISES {Rd.EndOfFile, Rd.Failure, Thread.Alerted}; PROCEDURE Init (view: View; start: I) RAISES {Rd.EndOfFile, Rd.Failure, Thread.Alerted}; PROCEDURE Bad (view: View) RAISES {Rd.EndOfFile, Rd.Failure, Thread.Alerted}; PROCEDURE Resize (view: View; n: CARDINAL) RAISES {}; END VTVirtual.