Re: and then... (a curiosity)

[stefan-lucks@see-the.signature]

> >> Nevertheless Boolean logic /= Belnap logic, though the former is contained
> >> in the latter. 
> > 
> > I never said "Boolean logic", I said "logic", which was ment to include 
> > multi-valued logic. ;-)
> 
> There are many multi-valued logics. 

You are trying to build an overly complex theory, which I am not 
interested in. The issue is very simple:

1. If the A- or the B-part in "if A and B" raises an exception, but the 
   other part is false, the "right thing" (TM) to do would be to transfer 
   control to the else clause (or below "end if", when there is no else). 
   The intermediate result can be viewed as a three-valued logic 
   expression, but the final outcome of the Boolean expression must be 
   Boolean, of course. 

2. If both raise A and B an exception, of if one raises an exception and 
   the other one is true, an exception is propagated. (*)

3. I would be willing to pragmatically sacrifice mathematical purity for a 
   shortcut rule: If A is false, the expression is false, whatever B does. 
   If A raises an exception, of if A is true and B raises an exception, 
   the exception is propagated.
 
----

(*) Funny problem: *Which* exception should be propagated? 
  
   
 


-- 
------ Stefan Lucks   --  Bauhaus-University Weimar  --   Germany  ------
               Stefan dot Lucks at uni minus weimar dot de
------  I  love  the  taste  of  Cryptanalysis  in  the  morning!  ------