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:virt,tx,gzz: What to do in undefined conditions :)


You point out excellently the problem of
> - undefined operations. What should the system do when rotating
>   to an empty cell as a dimension, for example

Let me throw out some general rules to consider--

1.  Don't crash.

2.  Consider the main thing that the particular functions do.

3.  Consider also what it's being extended to.

4.  Think of what the optimistic user might expect
 from the Undefined operation, possibly from some strange
 thing he's done.

5.  Try to make this sensible.

6.  Try to reconcile this with the overall conceptual structure.

In the case of the empty cell on the dimension list,
 my thoughts might be
(2)  The dimension list lets you see different views.
(3)  It's being extended to such things as parameters, numbers,
 maybe colors ... simply by putting in these new abbreviations--
 n.3, whatever.

The optimistic user might say, "hey, I can put anything I want
 in a cell, and that's what will appear on the view diagram!".
So why not?  Show blank on the view diagram, have a dimension
 with the null name?

I have no doctrinal position on this; if you want to forbid
 dimensions, for instance, without "c." where c is one (or more)
 characters, that's fine with me.

Rule 1 is the most important !-)

Best, T

Theodor Holm Nelson              
Project Professor, Keio University SFC Campus, Fujisawa, Japan
Visiting Professor, University of Southampton, England
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