D features

[Jonathan M Davis]

On Tuesday, September 20, 2011 14:02 Steven Schveighoffer wrote:
> On Tue, 20 Sep 2011 15:58:06 -0400, Rishat Galiulin
> > 2) Why D not using functions exceptions specification list like Java? If
> > this promotes bad programming style to newbies, may be better at least
> > to create compilation warnings?
> 
> Not sure what the question is, D does not support exception specification
> because exception specifications are too cumbersome to be useful.
> However, it does support saying that a function does *not* throw
> exceptions via the nothrow attribute.

Checked exceptions have generally been determined to have been a bad idea. 
They _seem_ like a good idea at first and do provide a number of benefits, but 
there are ultimately a number of problems with them. Java is the only language 
that I'm aware of that has checked exceptions. Both C# and D decided that they 
weren't a good idea and don't have them. This interview with one of the 
designers of C# gives some insight into the issues with checked exceptions: 
http://www.artima.com/intv/handcuffs.html

Ultimately, it means that documentation needs to be clear about what 
exceptions something is expected to throw, and it does mean that it can be 
harder to make sure that your code is prepared for every exception type that 
it should be without catching Exception, but it still works quite well.

Ideally, we'd have something that would statically verify that all of the 
appropriate exception types have been handled, but as far as I know, no one 
has really come up with a way to do that which doesn't have the problems that 
checked exceptions do.

- Jonathan M Davis