Disallowing break label (and continue label) inside an expression switch

Brian Goetz brian.goetz at oracle.com
Thu Mar 8 19:36:12 UTC 2018

Jan has updated the prototype to make the switch expression a bubble 
penatrable only by exceptions.  Please take a look!

On 3/2/2018 9:30 AM, Remi Forax wrote:
> Hi all,
> as far as i remember, the current idea to differentiate between a break label and a break value is to let the compiler figure this out,
> i wonder if it's not simpler to disallow break label (and continue label) inside an expression switch.
> After all, an expression switch do not exist yet, so no backward compatibility issue, it may make some refactoring impossible but had the great advantage to do not allow a lot of puzzler codes like the one below.
> enum Result {
>    ONE, MANY
> }
> Result result(String[] args) {
>    ONE: for(String s: args) {
>       return switch(s) {
>         case "several":
>         case "many":
>           break MANY;
>         case "one":
>           break ONE;
>         default:
>           continue;
>       };
>    }
>    throw ...;
> }
> Rémi

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