Re: The Right Approach to Exceptions

[deadalnix]

Le 21/02/2012 22:15, Andrei Alexandrescu a écrit :
What if instead of catching by class, we catch by attribute matching?
So instead of writing:
try { ... }
catch(SomeExceptionType e) { ... }
catch(SomeOtherExceptionType e) { ... }
catch(YetAnotherSillyException e) { ... }

we write:

try { ... }
catch(e: exists!e.filename&& e.failedOp is File.open) {
// something
}
catch(e: e.is_transient&& e.num_retries< 5) {
// something else
}
// And why should we even need an exception object in the first
// place?
catch(time()>= oldtime+5000) {
// This thing's been running for way too long, time to
// do something drastic
}

Flamesuit on! ;-)

The only problem I see here is ascribing e a type.


That is why I proposed here : 
http://forum.dlang.org/thread/jhos0l$102t$1...@digitalmars.com?page=25#post-jhtus4:2416tp:241:40digitalmars.com 
some alternative syntax. To make it short :

try {
    // Stuff . . .
} catch(Exception e) if(e.transient == false) {
    // Handling . . .
}

For the longer explanation, see the link.