[Aldor-l] Exceptions in aldor

[Ralf Hemmecke]

On 03/31/2006 12:49 PM, W Naylor wrote:
> In particular, I notice the last example in chapter 11 of the aldor user 
> guide defines a couple of Categorys extending 'Exception'. As far as I can 
> make out the Category Exception does not exist

That is right. All the Exceptions in libaldor are just of type
Category if they end in "ExceptionType" (some kind of convention) and 
ordinary domains if you see

   SOMEException: SOMEExceptionType == add {...}

(Of course you can have paremeters and everything.)

So exceptions are domains and their types are categories. There is 
actually no language defined type "Exception".

I haven't tried, but I belief, it would be perfectly possible to say 
something like

try {
    throw Integer;
} catch E in {
   E has Monoid => foo();
}

Maybe one of the Aldor developers could say more.

Ralf