code which ensures that the records of parent viewers & positions within them attached to voice viewers are kept consistent as the parent viewers are edited

n.b. no consideration given in this code to the existence of split viewers

IO USING [PutFR, int],

TextEdit USING [Size],

TiogaButtons USING [TextNodeRef],

TiogaOps USING [GetSelection, StepForward],

TiogaOpsDefs USING [Location, Ref],

ViewerClasses USING [Viewer],

ViewerEvents USING [EventRegistration, EventProc, RegisterEventProc, UnRegisterEventProc],

VoiceInText USING [DebugRope],

VoiceViewers USING [VoiceViewerInfo, voiceViewerInfoList],

SourceMarkerTracking;

viewer: ViewerClasses.Viewer,

destroyProc: ViewerEvents.EventRegistration

this is a list of all the viewers in which source markers have been created and which therefore have a destroyProc set up to sever parent links. When the destroyProc is called the viewer will be deleted from this list; however when all relevant source markers have been deleted from the viewer we do not bother to delete it from the list

called everytime a source marker is created within a text viewer

alreadyInList: BOOLEAN ← FALSE;

FOR l: LIST OF ViewerAndDestroyProc ← registeredViewerList, l.rest WHILE l # NIL AND ~alreadyInList DO IF l.first.viewer = viewer THEN alreadyInList ← TRUE ENDLOOP;

IF ~alreadyInList THEN

{ newEntry: ViewerAndDestroyProc ← [viewer, ViewerEvents.RegisterEventProc[
   proc: DestroyViewerEvent, event: destroy, filter: viewer, before: TRUE]];

}

firstEntry: BOOLEAN ← viewer = registeredViewerList.first.viewer;

previousEntry: LIST OF ViewerAndDestroyProc ← registeredViewerList;

IF ~firstEntry THEN WHILE previousEntry.rest.first.viewer # viewer DO previousEntry ← previousEntry.rest ENDLOOP; -- if this runs off the end then something has gone seriously wrong

ViewerEvents.UnRegisterEventProc[(IF firstEntry THEN registeredViewerList ELSE previousEntry.rest).first.destroyProc, destroy];

IF firstEntry THEN registeredViewerList ← registeredViewerList.rest ELSE previousEntry.rest ← previousEntry.rest.rest;

RemoveParentPointersTo[viewer];

FOR info: VoiceViewers.VoiceViewerInfo ← VoiceViewers.voiceViewerInfoList, info.nextInfoRec WHILE info # NIL DO

ENDLOOP

called before the primary selection is deleted, if in a text viewer

N.B. that the selection may span more than one node

viewer: ViewerClasses.Viewer;

start, end, current: TiogaOpsDefs.Location;

infoList: LIST OF VoiceViewers.VoiceViewerInfo ← NIL;

SeverLinks: PROC [node: TiogaOpsDefs.Ref, from, to: INT] = {

};

[viewer: viewer, start: start, end: end] ← TiogaOps.GetSelection[];

FOR info: VoiceViewers.VoiceViewerInfo ← VoiceViewers.voiceViewerInfoList, info.nextInfoRec WHILE info # NIL DO IF info.parentViewer = viewer THEN infoList ← CONS [info, infoList] ENDLOOP;

IF infoList = NIL THEN RETURN;

we now have a list of all the voice viewers whose parent links point at the viewer containing the primary selection: we need to go through all the nodes in the selection severing the links which point within the selection and altering those which lie in the last node of the selection, beyond the end of the selection

IF start.node = end.node

THEN SeverLinks[start.node, start.where, end.where]

ELSE

{ current ← start;

};

{ positionAdjustment: INT ← end.where - start.where + 1;

}