Okay, Maurizio, you got me thinking. As long as we are convinced that we are
actually going to use an explicit value-returning statement within a switch
expression quite infrequently in real code, why don’t we get the best of both
worlds by spelling it this way:
break return x;
Then everybody is happy:
(1) Cannot be confused with the old `break` syntax.
(2) Clearly exits a `switch` like `break` does.
(3) Clearly returns a value like `return` does.
(4) Better encourages exclusive use of `->` (because using `->` rather than `:
break return` saves even more characters than using `->` rather than `: break`).
(5) In the year 2364, this can be further generalized to allow `continue return
x;`.
(6) Those who want new language features to really jump out will surely be
satisfied.
—Guy
> On Mar 15, 2018, at 5:13 PM, Maurizio Cimadamore
> <maurizio.cimadam...@oracle.com> wrote:
>
> So, from a language design perspective, 'return x' is wrong - but, as you
> point out, we already committed the original sin of having 'return == local
> return' for lambdas, so I'm not too convinced that we couldn't use the same
> story again here. E.g. when you say 'return', what you really mean is
> 'returning from the innermost context'. This could be a method (as usual), or
> a nested expression e.g. a lambda or a switch expression.
>
> Kevin has a point in that using return is mildly worrisome when it comes to
> refactoring; but we had exactly the same problem with lambdas when we were
> considering migrating code using internal iteration (for loop) to code using
> external iteration (Stream forEach) - again, there the refactoring could not
> be 100% smooth - if the body of your loop had some abnormally completing
> branches, then there was no way to translate that into an external iteration
> idiom - at least not mechanically (e.g. 'return x' already meant something
> different inside old-style for loop bodies).
>
> So, seems to me that we end up with the same bag of pros and cons? E.g. more
> familiar to the user (return <expr> is something that they know and love),
> but more smelly from a design point of view (in a way that forecloses using
> 'return' to mean non-local return, but I wonder - has that ship already
> sailed?)
>
> Maurizio
