[Oberon] I have been defeated.

Andreas Pirklbauer andreas_pirklbauer at yahoo.com
Sun Jun 26 00:23:07 CEST 2016


Douglas,
In Experimental Oberon, the changes to the original are *also* seen in a clone created by System.Clone. In fact, its copy behaviour is exactly the same as System.Copy, except that the copy is created in a separate virtual logical display area. I'm not so familiar with Blackbox, but I used the term "deep" as it it used in the Project Oberon book section 4.4.2 (referring to the way descendants of a composite object are copied):
"As a fine point we clarify that the above algorithm is designed to create a deep copy of a composite object (a menu viewer in our case). If a shallow copy would be desired, the descendants would not have to be copied, and the original descendants instead of their copies would be attached to the copy of the composite object."
It's just semantics..Andreas

      From: Douglas G. Danforth <danforth at greenwoodfarm.com>
 To: Andreas Pirklbauer <andreas_pirklbauer at yahoo.com>; ETH Oberon and related systems <oberon at lists.inf.ethz.ch> 
 Sent: Saturday, June 25, 2016 10:58 PM
 Subject: Re: [Oberon] I have been defeated.
   
 Andreas,
 In BlackBox the "clone" is a shallow copy so that changes to the
 original are seen in the clone.  One simply has two views of the
 same "model" (document).
 -Doug Danforth
 
 On 6/25/2016 3:38 AM, Andreas Pirklbauer wrote:
  
 An alternative approach to the "too many copies of the same viewer" problem has been experimented with in Experimental Oberon ( https://github.com/andreaspirklbauer/Oberon-experimental ). There, each menu viewer has a "System.Clone" command in its title bar, which opens a clone (=deep copy) of the viewer in a new virtual display area, which is created on the fly. No overlaying tracks and no "hidden viewers". It's an experiment, so it would be interesting to hear what people think and how it could potentially be improved. 
  
 
 

  
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