dmd 1.046 and 2.031 releases

[Chad J]

Chad J wrote:
> Andrei Alexandrescu wrote:
>> Chad J wrote:
>>> These bugs always take me no less than 2 hours to find, unless I am
>>> specifically looking for fall-through bugs.
>> I agree. Probably a good option would be to keep on requiring break, but
>> also requiring the user to explicitly specify they want fallthrough in
>> the rare case when they do want it. I'd love to use "continue" for that
>> but it's already "occupied" by cases like while (...) switch (...).
>> Requiring !break or ~break would work but is a bit too cute. Adding a
>> new keyword or a whole new switch statement is too much aggravation. I
>> guess we'll have to live with it...
>>
>>
>> Andrei
> 
> Don't marginalize something that's important!
> 
> The syntax is arbitrary.  Just pick something that works.
> 
> Also, IIRC, the main argument in favor of fallthrough behavior was
> compatibility with C code.  Now that we have "final switch", we can,
> with reasonable certainty, assume that no C coder has written "final
> switch(...) ...".  Thus we are allowed to choose a syntax that's
> different without breaking anything.  And for those few people that want
> to write Duff's device, they can just use the old style switch-case.
> 
> <rambling and syntax>
> I'm personally a bit biased to the haXe switch-case statements that I've
> been using for the past few months.  In haXe you don't even have to
> write break; at the end, it will always exit the statement at the end of
> a case-block.  It also has that behavior added in final switch where
> switching on an enum requires you to be exhaustive about your handling
> of the possibilities.  It has worked well.  If it isn't powerful enough,
> there's always "goto label;" where label is either some external label
> or the name of one of the cases.  I think I've seen that in C#.  That
> also worked well.
> 
> So something like this:
> 
> final switch( foo )
> {
> 	case 0: goto 1; // emulate the fallthrough
> 	case 1: writefln("Got a zero or a one.");
> 	case 2: writefln("This isn't supposed to happen.");
> }
> 
> I wouldn't complain if it was done some other way though.  Just killing
> the fallthrough bugs would make me so much happier.
> </rambling and syntax>

Err, forgot to show usage in the example.

auto foo = 0;

final switch( foo )
{
	case 0: goto 1; // emulate the fallthrough
	case 1: writefln("Got a zero or a one.");
	case 2: writefln("This isn't supposed to happen.");
}

// "Got a zero or a one." is printed.