exception keyword

[DartBot]

This issue was originally filed by rtimo...@gmail.com

---

interface OutOfBeerException extends Exception {
  String get brand();
}

becomes

exception OutOfBeer { // interface
  String get brand();
}

[kasperl]

Added Area-Language, Triaged labels.

[gbracha]

One must weigh the pros and cons for any syntactic sugar.

Adding a keyword is always a big deal, as it may invalidate existing code (including Javascript or Java code people might wish to port to Dart). Pseudo-keywords are unattractive as well, as they create confusion as to when they are allowed and when not. So the cons are substantial.

On the pro side, what do we gain? Many (probably most) exception types are not direct subclasses of Exception, but more specialized, in which case this avails you nothing.

All in all, it is much more trouble than it is worth.

---

Set owner to @gbracha.
Added WontFix label.