JEP325: Switch expressions spec

[Guy Steele]

I agree; and that is exactly why I would throw in a newline in situations where I cared to use two arrows:

	case pat1 ->
	case pat2 -> s1;

is much to be preferred to

	case pat1 -> case pat2 -> s1;

Look, I also think that it’s bad form to write

	a = b ? c : d;

because of the risk of misinterpretation; I would write

	a = (b ? c : d);

I don’t think the risks of switch syntax are worse (or better) than this.

> On Apr 23, 2018, at 3:07 PM, forax at univ-mlv.fr wrote:
> 
> '->' being a two characters symbol (at least if you do not enable font ligature of your IDE/editor) is a more strong separator than comma ',',
> so i think it's easy to visually parse
>  case pat1, pat2 -> s
> as
>  case [pat1, pat2] -> s
> than
>  case pat1, [pat2 -> s]
> 
> Rémi
> 
> ----- Mail original -----
>> De: "Guy Steele" <guy.steele at oracle.com>
>> À: "Remi Forax" <forax at univ-mlv.fr>
>> Cc: "amber-spec-experts" <amber-spec-experts at openjdk.java.net>
>> Envoyé: Lundi 23 Avril 2018 20:32:26
>> Objet: Re: JEP325: Switch expressions spec
> 
>>> 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