On 5/10/2018 10:36 AM, Dan Smith wrote:
On May 10, 2018, at 6:28 AM, Gavin Bierman
<gavin.bier...@oracle.com> wrote:
15.29 "the switch expression completes normally": More
conventionally, "the value of the switch expression is …"
That phrase occurs in several places, so you’ll have to tell me
which one you don’t like.
"If execution of the Statement completes abruptly for the reason of a
break with a value, then the switch expression completes normally
with that value."
I'd suggest changing to "for the reason of a break with a value _V_,
then the value of the switch expression is _V_."
For comparison, in all of Chapter 15, I only find four usages of the
phrase "complete[s] normally". Lots of usages of "complete[s]
abruptly", though. Switch _bodies_ are special, because they contain
statements, so it makes sense to say "completes normally" here. But
once we've left the body and we're talking about the switch
expression as a whole, it's better to use the expression-oriented
terminology.
I agree that expressions completing normally has rarely been spelled out
in Ch.15, and that the value resulting from evaluation of the expression
is usually more interesting.
However, JEP 325 is the first time that the JLS will explicitly pend an
expression's evalation on a statement's completion. Usually it's the
other way round, per 14.1: "If a statement evaluates an expression,
abrupt completion of the expression always causes ...". And lambda
expressions, with bodies containing statements, didn't need to do it
explicitly in 15.27.2 or 15.27.4.
So, since a value-break statement is a common way out of a switch
expression, I would like the JLS to put the completes-abruptly side by
side with a completes-normally. The abrupt completion of `break e;` is
"swallowed" by the normal completion of the enclosing switch expression.
(This appeals to the disrupted completion that `catch` and `finally`
clauses arrange.)
AND, the JLS should specify the value of the switch expression, based on
evaluating the argument of the value-break statement, as you have proposed.
Alex
