JEP325: Switch expressions spec

Guy Steele guy.steele at oracle.com
Mon Apr 23 18:32:26 UTC 2018


> On Apr 23, 2018, at 2:27 PM, Guy Steele <guy.steele at oracle.com> wrote:
> 
> Good point, Rémi.  However, note that
> 
> 	case pat1, pat2 -> s
> 
> is equally too close to
> 
> 	case pat1 -> pat2 -> s
> 
> and again they have very different meanings.
> 
> We have to admit that there is room to blunder with this syntax.
> 
> One way out would be to use a different arrow for `switch` statements:
> 
> 	switch (x) {
> 		case pat1 => case pat2 => s1;
> 		case pat3 => pat4 -> s2;
> 		case pat5, pat6 => s2;
> 		case pat7, pat8 => pat9 -> s4;
> 	}

As a careful coder, if I did not have a separate arrow `=>` (and probably even if I did), I would use formatting and parentheses to convey my intent:

	switch (x) {
		case pat1 ->
		case pat2 -> s1;
		case pat3 -> (pat4 -> s2);
		case pat5, pat6 -> s2;
		case pat7, pat8 -> (pat9 -> s4);
	}

—Guy



More information about the amber-spec-observers mailing list