DMD 0.170 release

[Reiner Pope]

Tom S wrote:
> 
> I'm not yet fully convinced if trailing delegates should be allowed 
> implicitly, just because a function's signature matches some criteria. A 
> special keyword like 'trailing' could be used for it. Of course, because 
> of a lack of a better keyword at the moment, we could just call it 
> 'static' <g>

Versus plain old delegates, trailing delegates can allow:
1. type inference of parameters
2. syntactic sugar to remove ';' at the end, making it look more native
3. continue/break/return behaviour.

1 and 2 are syntactic sugar for the call-site; therefore, they should be 
allowed implicitly.

3 is special behaviour and shouldn't be allowed implicitly. However, I 
don't think a new keyword is required. Just make an enum:

enum IterationResult { CONTINUE, BREAK, RETURN };

and the break/continue behaviour is then only possible when the function 
has a delegate as a second-last parameter, and IterationResult as the last.

Cheers,

Reiner