MODULE EditorXtra;

IMPORT TextPort, VText;

IMPORT VTDef, Rd, Thread;

PROCEDURE TopLineIndex(tp: TextPort.T): INTEGER =

Return the character position of the beginning of the first visible line of tp.

  <* FATAL VTDef.Error *>
  BEGIN
    RETURN VText.StartIndex(TextPort.GetVText(tp),0)
  END TopLineIndex;

PROCEDURE IndexToTop(tp: TextPort.T; i: INTEGER) =
  <* FATAL Rd.EndOfFile, Rd.Failure, Thread.Alerted, VTDef.Error *>
  BEGIN
    VText.SetStart(TextPort.GetVText(tp), 0, i)
  END IndexToTop;

BEGIN
END EditorXtra.