[Oberon] Viewer marking.

6 Mar 2018

      ...
MarkingTest.T always reports "A Text viewer is marked."  Pressing F2 
to remove the marker has no effect.  How is viewer marking detected  correctly?
If you can modify module Oberon, just add the following procedure

  PROCEDURE PointerOn*(): BOOLEAN;
  BEGIN RETURN Pointer.on
  END PointerOn;

and use it as follows:

  MODULE M;
  IMPORT Viewers, Texts, Oberon;
  VAR W: Texts.Writer;

  PROCEDURE P*;
    VAR V: Viewers.Viewer; X, Y: INTEGER;
  BEGIN
    IF Oberon.PointerOn() THEN V := Oberon.MarkedViewer();
      Texts.WriteString(W, "A viewer is marked and its coordinates are");
      Texts.WriteInt(W, V.X, 4); Texts.WriteInt(W, V.Y, 4)
    ELSE Texts.WriteString(W, "No viewer is marked.")
    END ;
    Texts.WriteLn(W); Texts.Append(Oberon.Log, W.buf)
  END P;

BEGIN Texts.OpenWriter(W)
END M.

ORP.Compile M.Mod ~
M.P

[Oberon] Viewer marking.

Andreas Pirklbauer