> On Apr 27, 2018, at 11:03 AM, Gavin Bierman <gavin.bier...@oracle.com> wrote:
>
> I have uploaded the latest draft of the spec for JEP 325 at
> http://cr.openjdk.java.net/~gbierman/switch-expressions.html
>
> Changes from the last version:
> * Supports new -> label form in both switch expressions and switch statements
> * Added typing rules for switch expression
> * Restrict the type of a selector expression to not include long, double and
> float as previously proposed
> * Misc smaller changes from community feedback (thanks!)
>
> Comments welcomed!
Note the (certainly currently intentional) lack of structural parallelism in
these two parts of the BNF in Section 4.11:
__________________________________
SwitchStatementClause:
ClauseLabel Statement
ClauseLabel:
CasePattern ->
__________________________________
SwitchBlockStatementGroup:
GroupLabels BlockStatements
GroupLabels:
GroupLabel {GroupLabel}
GroupLabel:
CasePattern :
__________________________________
They can easily be made structurally parallel by changing the first two cited
rules to:
__________________________________
SwitchStatementClause:
ClauseLabels Statement
ClauseLabels:
ClauseLabel {ClauseLabel}
ClauseLabel:
CasePattern ->
__________________________________
which of course results in precisely my earlier proposal to allow multiple
clause labels on a single statement—this note is merely to point out that it is
an easy and unsurprising change to the BNF.
Then in Section 15.29 one need only change
__________________________________
SwitchExpressionClause:
ClauseLabel Expression ;
ClauseLabel Block
ClauseLabel ThrowStatement
__________________________________
to
__________________________________
SwitchExpressionClause:
ClauseLabels Expression ;
ClauseLabels Block
ClauseLabels ThrowStatement
__________________________________
“It’s not fallthrough—it’s multiple labels.”
—Guy
