We can start on later now. We can warn on conditionals where the two would
give a different answer, nudging people to fix their code, and then bring them
into alignment after everyone has been suitably irritated by warnings.
> On Mar 31, 2018, at 7:13 AM, Doug Lea <d...@cs.oswego.edu> wrote:
>
> On Sat, March 31, 2018 6:23 am, fo...@univ-mlv.fr wrote:
>> The fact that the semantics of ?: is very ad-hoc is a kind of accident of
>> the history,
>> we may want to fix it but i do not see why we have to fix it at the same
>> time that we introduce the expression switch,
>> we can fix the semantics of ?: later or never.
>
> Where "later" probably means "never". It should be fixed now.
> I agree that (B) and (C) are basically the same, so choose (C).
> I've had to fiddle with :? to get the compiler to shut up about
> reasonable-looking expressions. (Sorry, I can't recall examples.)
> Having the same story for both of them would be best, assuming
> that existing code doesn't break.
>
> -Doug
>
>>
>> Rémi
>>
>> ----- Mail original -----
>>> De: "daniel smith" <daniel.sm...@oracle.com>
>>> À: "Remi Forax" <fo...@univ-mlv.fr>
>>> Cc: "amber-spec-experts" <amber-spec-experts@openjdk.java.net>
>>> Envoyé: Samedi 31 Mars 2018 03:44:49
>>> Objet: Re: Feedback wanted: switch expression typing
>>
>>>> On Mar 30, 2018, at 10:54 AM, Remi Forax <fo...@univ-mlv.fr> wrote:
>>>>
>>>> I do not see (B) as sacrifying the consistency because the premise is
>>>> that an
>>>> expression switch should be consistent with ?:
>>>>
>>>> But an expression switch can also be modeled as a classical switch that
>>>> returns
>>>> it's value to a local variable.
>>>>
>>>> int a = switch(foo) {
>>>> case 'a' -> 2;
>>>> case 'b' -> 3;
>>>> }
>>>> can be see as
>>>> int a = $switch(foo);
>>>> with
>>>> int $switch(char foo) {
>>>> case 'a': return 2;
>>>> case 'b': return 3;
>>>> }
>>>
>>> I mean, sure, this is another way to assert "switches in assignment
>>> contexts
>>> should always be poly expressions".
>>>
>>> But it's just as easy to assert "conditional expressions in assignment
>>> contexts
>>> should always be poly expressions".
>>>
>>> int a = test ? 2 : 3;
>>> can be seen as
>>> int a = $conditional(test);
>>> with
>>> int $conditional(boolean test) {
>>> if (test) return 2;
>>> else return 3;
>>> }
>>>
>>> Those are probably good principles. But if we embrace them, we're doing
>>> (C).
>>>
>>> —Dan
>>
>
>
