Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!mailrus!purdue!mentor.cc.purdue.edu!pur-ee!pur-phy!sawmill!mdbs!wsmith
From: wsmith@mdbs.UUCP (Bill Smith)
Newsgroups: comp.lang.c++
Subject: Re: Shippable Objects
Keywords: Leif
Message-ID: <1469@mdbs.UUCP>
Date: 13 Dec 89 16:17:41 GMT
Organization: MDBS Inc., Lafayette, IN
Lines: 23

I have done more thinking about my technique of storing objects in a file
that I used in Leif.  As I feared, I did not address some of the more 
difficult problems which will make my solution inadequate for the general case.

The problems that I can think of off the top of my head are:

1.  Pointers into the middle of a structure:
	There is not clean way to find the beginning of the
	structure that is being addressed in this way.
2.  Pointer pointers that are not pointers to an array of pointers:
	Pointer pointers are usually pointers into the middle
	of a structure and even when they are not, there isn't normally
	room allocated to give the traversal algorithm something to 
	bite on.

It is a difficult problem if you do not make a few simplifying assumptions
or build hooks into the language implementation that make finding the
necessary information for a depth first or breadth first traversal of
the data in a computationally efficient way.   

Bill Smith
(the known world)!pur-ee!mdbs!wsmith
(Not mdbs opinions)