Just to clarify : it will crash not because `nil` passed, but because there
is no check for `nil` in the function itself. I.e. nobody prevents you to
make a function that *will* check the nil and at the same time use all the
bonuses from implicitly unwrapped optional parameter:
func foo(_ i: Int!) {
guard i != nil else {return}
print(i) // use IUO parameter
}
foo(nil) // no errors
foo(1) // 1
On 09.06.2016 11:04, Spromicky via swift-evolution wrote:
Yep, but no one stop you if you pass optional value. And in runtime it crash in
case if it really will be `nil`. But from other side non-optional params make
the same, and does not let you pass an optional value, and show error on
compile time. This make your code more safety.
Now force unwrapped params in function used only if you use old Obj-C code
without nullability modifiers, so no sense, i think, for clear swift code.
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<[email protected]>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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