On 12/24/12 2:11 AM, bearophile wrote:
Recently Ada 2012 was accepted as ISO standard, and on the good Lambda
the Ultimate blog there is a small thread about it, with an interesting
post:
http://lambda-the-ultimate.org/node/4661#comment-73731
The post makes two simple valid points, worth considering.
Currently in D this code compiles with no errors:
void main() {
bool b;
final switch (b) {
case true:
break;
}
}
And gives at run-time:
core.exception.SwitchError@test(3): No appropriate switch clause found
It's one of my top fifteen bug reports (it was mislabelled as
enhancement request):
http://d.puremagic.com/issues/show_bug.cgi?id=5713
In my opinion It's a topic worth discussing and fixing.
Yes, this is a bug in the language design (as much as the "method is
hidden" exception that I recall we got rid of).
The simplest solution is to statically disallow "final switch" to
operate on anything bug enums.
I'd say we eradicate the exception altogether. Again, it reflects
incompleteness in language's approach. Requiring people to add a
default: {}
whenever they don't care about certain cases is a low price to pay for
ensuring everybody stays in sync.
Andrei
