hexdreamer
(Kenny Leung)
1
Hi All.
It seems that if you have an escaping closure argument, you can’t make it optional. Am I right?
init (
owner:AnyObject,
handler:@escaping (HXObserverNotification)->Void
) {
self.owner = owner
self.handler = handler
}
You could try this:
init (
owner:AnyObject,
handler:@escaping ((HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute only applies to function types”
Or you could try this:
init (
owner:AnyObject,
handler:(@escaping (HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute may only be used in function parameter position”
-Kenny
knatt
(Kevin Nattinger)
2
If you remove the @escaping you'll notice it doesn't complain about a non-escaping closure escaping.
I could be wrong, but I believe that's because using it as an associated value forces it to escape on the calling side.
func esc(_ x: @escaping () -> ()) {
x()
}
func noesc(_ x: () -> ()) {
x()
}
func foo() {
noesc {
print(owner) // compiles
}
esc {
print(owner) // error: requires explicit 'self.'…
}
Optional<()->()>.some {
print(owner) // error: requires explicit 'self.'…
}
}
···
On Jan 5, 2018, at 11:48 AM, Kenny Leung via swift-users <swift-users@swift.org> wrote:
Hi All.
It seems that if you have an escaping closure argument, you can’t make it optional. Am I right?
init (
owner:AnyObject,
handler:@escaping (HXObserverNotification)->Void
) {
self.owner = owner
self.handler = handler
}
You could try this:
init (
owner:AnyObject,
handler:@escaping ((HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute only applies to function types”
Or you could try this:
init (
owner:AnyObject,
handler:(@escaping (HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute may only be used in function parameter position”
-Kenny
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
hexdreamer
(Kenny Leung)
3
Because it’s being assigned to an ivar, it’s forced to be escaping, or so the compiler tells me.
-Kenny
···
On Jan 5, 2018, at 12:04 PM, Kevin Nattinger <swift@nattinger.net> wrote:
If you remove the @escaping you'll notice it doesn't complain about a non-escaping closure escaping.
I could be wrong, but I believe that's because using it as an associated value forces it to escape on the calling side.
func esc(_ x: @escaping () -> ()) {
x()
}
func noesc(_ x: () -> ()) {
x()
}
func foo() {
noesc {
print(owner) // compiles
}
esc {
print(owner) // error: requires explicit 'self.'…
}
Optional<()->()>.some {
print(owner) // error: requires explicit 'self.'…
}
}
On Jan 5, 2018, at 11:48 AM, Kenny Leung via swift-users <swift-users@swift.org <mailto:swift-users@swift.org>> wrote:
Hi All.
It seems that if you have an escaping closure argument, you can’t make it optional. Am I right?
init (
owner:AnyObject,
handler:@escaping (HXObserverNotification)->Void
) {
self.owner = owner
self.handler = handler
}
You could try this:
init (
owner:AnyObject,
handler:@escaping ((HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute only applies to function types”
Or you could try this:
init (
owner:AnyObject,
handler:(@escaping (HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute may only be used in function parameter position”
-Kenny
_______________________________________________
swift-users mailing list
swift-users@swift.org <mailto:swift-users@swift.org>
https://lists.swift.org/mailman/listinfo/swift-users
At the moment an optional closure is considered escaping so you don’t have
to state it using @escaping and as you see you actually can’t. A bug or two
exists against Swift related this and I don’t know their current state.
If after removing @escaping things still fail to compile please post a code
example.
-Shawn
···
On Fri, Jan 5, 2018 at 1:17 PM Kenny Leung via swift-users < swift-users@swift.org> wrote:
Because it’s being assigned to an ivar, it’s forced to be escaping, or so
the compiler tells me.
-Kenny
On Jan 5, 2018, at 12:04 PM, Kevin Nattinger <swift@nattinger.net> wrote:
If you remove the @escaping you'll notice it doesn't complain about a
non-escaping closure escaping.
I could be wrong, but I believe that's because using it as an associated
value forces it to escape on the calling side.
func esc(_ x: @escaping () -> ()) {
x()
}
func noesc(_ x: () -> ()) {
x()
}
func foo() {
noesc {
print(owner) // compiles
}
esc {
print(owner) // error: requires explicit 'self.'…
}
Optional<()->()>.some {
print(owner) // error: requires explicit 'self.'…
}
}
On Jan 5, 2018, at 11:48 AM, Kenny Leung via swift-users < > swift-users@swift.org> wrote:
Hi All.
It seems that if you have an escaping closure argument, you can’t make it
optional. Am I right?
init (
owner:AnyObject,
handler:@escaping (HXObserverNotification)->Void
) {
self.owner = owner
self.handler = handler
}
You could try this:
init (
owner:AnyObject,
handler:@escaping ((HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute only applies to function types”
Or you could try this:
init (
owner:AnyObject,
handler:(@escaping (HXObserverNotification)->Void)?
) {
self.owner = owner
self.handler = handler
}
You get “@escaping attribute may only be used in function parameter
position”
-Kenny
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
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