[swift-evolution] [Proposal] Remove force unwrapping in function signature.

[Javier Soto]

I agree we could disallow explicitly declaring implicitly unwrapped
function parameters, but this will be needed for the clang importer since
there will still be many C and ObjC APIs not tagged for nullability.
On Wed, Jun 8, 2016 at 2:46 PM Saagar Jha via swift-evolution <
swift-evolution at swift.org> wrote:

> +1 I agree. Unwrapping in the functional signature is confusing for the
> user; many don’t realize that it puts the burden of checking on them.
> Non-optional function parameters make this explicit by preventing passing
> in Optional types, forcing the user to check, which they should be doing
> anyway.
>
> On Wed, Jun 8, 2016 at 12:22 PM J. Charles M. N. via swift-evolution <
> swift-evolution at swift.org> wrote:
>
>>
>> This confused me at the beginning.
>>
>> But doesn't Int! In parameter type means the function is awaiting an
>> unwrapped value so the user should ensure that it data parameter is
>> available, valid, and unwrapped?
>>
>> --
>> J. Charles
>>
>> > Le 8 juin 2016 à 13:30, Spromicky via swift-evolution <
>> swift-evolution at swift.org> a écrit :
>> >
>> > Hello, everyone!
>> >
>> > I wanna propose to you to remove force unwrapping in fuction signature
>> for swift code. That no sense in clear swift code. If we wanna use some
>> optional value as function param, that is not optional, we must unwrap it
>> before function call.
>> > People who new in swift look at how they old Obj-C code (without
>> nullability modifiers) translate in to swift:
>> >
>> > Obj-C:
>> > - (void)foo:(NSInteger)bar {
>> >    //...
>> > }
>> >
>> > Swift transaliton:
>> > func foo(bar: Int!) {
>> >    //...
>> > }
>> >
>> > And think that force unwrapping in signature is good practice. And
>> start write functions in clear swift code like this:
>> >
>> > func newFoo(bar: Int!) {
>> >    //...
>> > }
>> >
>> > and use it like this:
>> >
>> > let bar: Int? = 1
>> > newFoo(bar)
>> >
>> > And it really work, and they does not think that this can crash in case
>> if `bar` will be `nil`.
>> > But in clear swift we wanna work with parametrs in function that
>> clearly or optional, or not.
>> >
>> > func newFoo(bar: Int) {
>> >    //...
>> > }
>> >
>> > or
>> >
>> > func newFoo(bar: Int?) {
>> >    //...
>> > }
>> >
>> > When we write a new function we know what we need in this case and use
>> optional params or not.
>> >
>> > So my proposal is remove force unwrapping(`!`) from function
>> signatures, cause it have no sense, and that confuse new users.
>> > _______________________________________________
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>> > swift-evolution at swift.org
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>>
> --
> -Saagar Jha
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>
-- 
Javier Soto
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