The Right Approach to Exceptions

[Zach]

On Sunday, 19 February 2012 at 01:29:40 UTC, Nick Sabalausky 
wrote:
> Another one for the file of "Crazy shit Andrei says" ;)
>
> From experience, I (and clearly many others here) find a 
> sparse, flat exception hierarchy to be problematic and 
> limiting. But even with a rich detailed exception hierarchy, 
> those (ie, Andrei) who want to limit themselves to catching 
> course-grained exceptions can do so, thanks to the nature of 
> subtyping. So why are we even discussing this?

How about we revisit ancient design decisions which once held 
true... but no longer is the case due to our "god-language" being 
more expressive?

In my experience an "exception hierarchy" is never good enough, 
it suffers from the same problems as most frameworks also do... 
they simplify/destroy too much info of from the original error.

ex why don't we throw a closure? Of course we could go crazy with 
mixins and CTFE,CTTI,RTTI aswell... imho the goal should not be 
to do as good as java, the goal is progress! Java should copy our 
design if anything... we could have a very rich exception 
structure... without the need for a hierarchy.

try(name) // try extended to support full closure syntax
{
   DIR* dir = opendir(toStringz(name));

   if(dir==0 && errno==ENOTDIR)
     throw; // throws the entire try block as a closure
}