> Am 28.05.2016 um 19:35 schrieb Austin Zheng <[email protected]>:
>
> Sorry, 'with' in the second example should be 'where'. My personal preference
> is to keep 'where' for both uses, since they are serving the same purpose.
>
>> On May 28, 2016, at 10:33 AM, Austin Zheng <[email protected]
>> <mailto:[email protected]>> wrote:
>>>
>>> -Thorsten
>>
>> We could make parentheses optional in the general case, and just have them
>> mandatory in the following situations:
>>
>> - You want to nest an existential literal inside another existential literal:
>> let a : Protocol1, (Protocol2 where .Blah == Int), Protocol3 = foo()
When using `&` instead of `,` this would not be required (not even for
readability IMO).
>>
>> - You want to return an existential with more than one term and/or a where
>> clause from a function that has a generic where clause
>> func foo<P, Q>(p: P, q: Q) -> (Collection with .Element == P) where P :
>> Equatable { … }
For return types (if staying with `where` instead of `with`) the parentheses
would be required iff only one `where` is present.
They would not be strictly required if two `where` clauses would be present,
but I would be ok if they would be mandatory in that case.
>>
>> - You want to use an existential as a function argument, and that
>> existential has more than one term and/or a where clause
>> func foo(x: Protocol1, y: (Protocol2 where .Blah == Int), z: Protocol3) { … }
I wouldn’t require them here. For one the function does not look too bad
without the parentheses:
func foo(x: Protocol1, y: Protocol2 where .Blah == Int, z: Protocol3) { … }
But even more important: when formatting this function across multiple lines
(which I might rather do to improve readability instead of adding parentheses)
I would definitely *not* want to have to use parentheses:
func foo(
x: Protocol1,
y: Protocol2 where .Blah == Int,
z: Protocol3)
{ … }
-Thorsten
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