[CCC] Object class comment

Andrew P. Black black at cse.ogi.edu
Tue Feb 29 00:55:24 UTC 2000


At 14:22 -0500 2000.2.28, Norton, Chris wrote:
>In addition to the other fine responses to your question (ProtoObject is the
>superclass of Object, et. al), I believe that people also define Proxy
>objects by subclassing nil (UndefinedObject), rather than Object.  Proxy
>objects are common ...


Unfortunately, since UndefinedObject is itself a subclass of Object, 
making Proxy a subclass of UndefinedObject does not achieve the 
desired effect.  (It does achieve one _undesired_ effect -- making 
all the Proxy objects print as nil!

I believe that the reasons for the creation of ProtoObject include 
the need to have a place to put Proxy objects that is not a subclass 
of Object.  ObjectOut and ImageSegmentRootStub are two proxy objects 
in the image that are subclsses of ProxyObject.  Marcel's Trampoline 
code should probably be modified so that Trampoline is a subclass of 
ProtoObject rather than UndefinedObject.






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