[Pharo-project] Improving Pharo's Exception Hierarchy

Toon Verwaest toon.verwaest at gmail.com
Thu Apr 14 14:08:19 CEST 2011

Right, so you confirm the experience of Dale.

In the case of flagging errors without classes, do you generally just 
use a simple symbol, or concatenate strings to convey more details? This 
last seems somehow a bad idea... but maybe if it's never caught it's not 
so relevant?


On 04/14/2011 02:03 PM, Hernan Wilkinson wrote:
> the problem is not related to technical issues (like how much machine 
> memory you save, etc). It is related to knowledge organization...
> If you have two classes that define exactly the same methods, inst 
> var, etc, why do you have two instead of one? If you answer is 
> "because of the name of the class", remember that names are 
> contextualized to the place where they are used...
> I mean, this is easy, just take all the places where exceptions are 
> handle in Smalltalk and look what the handlers do with the exceptions. 
> You will see that in almost all cases the exceptions are not used at 
> all, the information they carry with them is not use at all... so, 
> from a theory point of view it looks nice to have a big exception 
> hierarchy but from the practical point of view is not only useless but 
> also more difficult to use.
> I build a system that had an exception class base on where they were 
> signal and not handled, we end up with around 1100 exceptions... only 
> 3 or 4 are handled directly

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