Re: Passing a swift function to objective-c
Hi Roland, Thanks for the followup. I've created a proper git rep on github rather than just a gist. Most of my github reps seem to be this kind of mini demonstration project and I was trying to avoid yet another one. https://github.com/SheffieldKevin/swift-objectivec What version of Xcode are you using by the way, Swift is so flux-y at the moment it probably makes a difference. I'm now running release Yosemite and release Xcode 6.1. That appears to me to make no difference. I still can't assign to the optional property of my protocol. You can ignore the ImageProvider2 class, I've just included it for completeness. It doesn't have a protocol and just declares the property itself. So with my protocol I've done something similar to what you did if I've interpreted your discussion correctly. I've got two properties, one that is required and one that is optional. Everything works fine for the required property. But I still can't get the optional one to work. In ImageProvider.m you'll see that the MakeImageProvider function assigns a block to the optional property and in SupplyCreateImage.swift I've commented out the assignment. I've provided the example this way so that it can be seen that it works when done using objective-c. But if you comment out the assignment to the optional property of the block, and uncomment the line in the swift file you'll see that the command line tool no longer compiles. Like you I've tried the use of the optional and playing around with casting but I've not actually got the code to compile this way. Kevin ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Passing a swift function to objective-c
I've now found an acceptable solution. Rather than a property I've added an optional method to the protocol which then in its implementation assigns using the property, pretty much to make sure that the function/block is copied. I declared the method like so: -(void)applyMyCreateImageFunction:(CGImageRef (^)(NSDictionary *))createImageFunction And when calling it from the swift code I call it like so: imageProvider.applyMyCreateImageFunction?(makeImage) The question mark was necessary to evaluate whether the optional protocol method had been implemented or not. Kevin On 18 Oct 2014, at 18:18, Kevin Meaney k...@yvs.eu.com wrote: Hi Roland, Thanks for the followup. I've created a proper git rep on github rather than just a gist. Most of my github reps seem to be this kind of mini demonstration project and I was trying to avoid yet another one. https://github.com/SheffieldKevin/swift-objectivec What version of Xcode are you using by the way, Swift is so flux-y at the moment it probably makes a difference. I'm now running release Yosemite and release Xcode 6.1. That appears to me to make no difference. I still can't assign to the optional property of my protocol. You can ignore the ImageProvider2 class, I've just included it for completeness. It doesn't have a protocol and just declares the property itself. So with my protocol I've done something similar to what you did if I've interpreted your discussion correctly. I've got two properties, one that is required and one that is optional. Everything works fine for the required property. But I still can't get the optional one to work. In ImageProvider.m you'll see that the MakeImageProvider function assigns a block to the optional property and in SupplyCreateImage.swift I've commented out the assignment. I've provided the example this way so that it can be seen that it works when done using objective-c. But if you comment out the assignment to the optional property of the block, and uncomment the line in the swift file you'll see that the command line tool no longer compiles. Like you I've tried the use of the optional and playing around with casting but I've not actually got the code to compile this way. Kevin ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/ktam%40yvs.eu.com This email sent to k...@yvs.eu.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Passing a swift function to objective-c
Thanks Roland.
On 17 Oct 2014, at 00:20, Roland King r...@rols.org wrote:
On 17 Oct 2014, at 6:13 am, Kevin Meaney k...@yvs.eu.com wrote:
Hi,
I'm beginning to feel this above my pay grade as I can't seem to work it out.
I have a framework in Objective-C. I've been writing some tests for it, and
to make life fun I've been writing the tests in Swift.
I have a property of a class in the objective-c framework declared like so:
@property (nonatomic, copy) CGImageRef (^createImage)(NSDictionary *);
In my tests I'm trying to write a function that I can assign to the property.
In the most basic form the function looks like this, I'm ignoring the passed
in dictionary for the purposes of asking this question:
func createCGImage2(dictionary: [NSObject:AnyObject]) - CGImage {
let jpegURL = NSBundle.mainBundle().URLForResource(myimage,
withExtension:jpg)
let imageSource = CGImageSourceCreateWithURL(jpegURL, nil)!
let theImage = CGImageSourceCreateImageAtIndex(imageSource, 0, nil)
return theImage
}
When I try to set the property with the function I get:
error: cannot convert the expression's type '([NSObject : AnyObject]) -
UnmanagedCGImage!' to type '(([NSObject : AnyObject]!) -
UnmanagedCGImage!)!?'
Now, if I have a function declared like so:
func createCGImageFromDictionary(dictionary: [NSObject:AnyObject]!) -
UnmanagedCGImage!
error: cannot convert the expression's type '([NSObject : AnyObject]!) -
UnmanagedCGImage!' to type '(([NSObject : AnyObject]!) -
UnmanagedCGImage!)!?'
I'm still a long way off. There's an extra () in there and an extra !? at
the end that I really don't know how to interpret. Also I don't know how to
convert the result of CGImageSourceCreateImageAtIndex to a
UnmanagedCGImage as a return value.
I've been through various bits of the documentation, but something isn't
clicking so that I understand how this stuff works so that I can try and
solve it.
Kevin
__
ok this simple test works for me .. I also don’t understand the extra parens
etc in your example. So where does your code differ from the below? Note I
set it both with a public function and a closure, just to see if it works.
A detail I should have included. The @property is declared in the optional
section of a protocol. I know the object in question has implemented the
property. But that explains the extra requirements for unwrapping.
I've put together a gist where I've attempted to play with this.
https://gist.github.com/SheffieldKevin/a06907e163885f249548
I got the assigning to a property working when that property was declared as
part of the class, but not when it has been declared in the optional section of
a protocol. So I was able to duplicate what you did Roland. But no matter what
I try, documentation I read I can't make it work when the property is declared
in the protocol.
I got myself distracted because the project I setup to try out stuff was an
objective-c command line tool and I also had trouble calling swift code from
Objective-c. I could not get a swift function that wasn't a class or instance
method to be callable from Objective-c.
Kevin
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Re: Passing a swift function to objective-c
On Oct 17, 2014, at 09:59 , Kevin Meaney k...@yvs.eu.com wrote: I got the assigning to a property working when that property was declared as part of the class, but not when it has been declared in the optional section of a protocol. So I was able to duplicate what you did Roland. But no matter what I try, documentation I read I can't make it work when the property is declared in the protocol. Presumably, the issue is that Swift makes assumptions about the possibility of a nil value when translating Obj-C frameworks types in a header. I believe that trying to guess the Swift translation from the Obj-C declaration will just drive you into madness. What you need to do instead is examine the translated declaration. Try Command-clicking on the protocol name in the place where you declare conformance, and you should see the translation. Then mimic the block type you see there. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Passing a swift function to objective-c
ok this simple test works for me .. I also don’t understand the extra parens
etc in your example. So where does your code differ from the below? Note I
set it both with a public function and a closure, just to see if it works.
A detail I should have included. The @property is declared in the optional
section of a protocol. I know the object in question has implemented the
property. But that explains the extra requirements for unwrapping.
I've put together a gist where I've attempted to play with this.
https://gist.github.com/SheffieldKevin/a06907e163885f249548
https://gist.github.com/SheffieldKevin/a06907e163885f249548
I got the assigning to a property working when that property was declared as
part of the class, but not when it has been declared in the optional section
of a protocol. So I was able to duplicate what you did Roland. But no matter
what I try, documentation I read I can't make it work when the property is
declared in the protocol.
I got myself distracted because the project I setup to try out stuff was an
objective-c command line tool and I also had trouble calling swift code from
Objective-c. I could not get a swift function that wasn't a class or instance
method to be callable from Objective-c.
Kevin
Right the optionality in the protocol is somewhat important and yes that does
explain why there’s the extra parens and ? around it. You’re certainly out in
some deeper water here with optional properties in a protocol which return
blocks in objective C being bridged over to Swift.
I can’t get your error message however. The stuff you posted on github might be
helpful if it were a full project, with xcode project file, which exhibits that
error message when built, ie it doesn’t actually build. I just can’t make it
fail. What version of Xcode are you using by the way, Swift is so flux-y at the
moment it probably makes a difference.
I made my own protocol with an optional (and a non-optional) property and used
it in Swift and I can assign to either of them with the method posted earlier
in the thread. I can actually defeat the compiler in a few ways, most notably
by casting to the protocol itself in which case it won’t let me assign the
property at all.
I thought of this …
x.createImage? = function
but that doesn’t work either. If x does implement createImage() but returns nil
because it’s not set yet then it doesn’t set it, if x doesn’t implement the
getter then it just crashes.
The one version I do have working is this piece of ugliness. Fruit is the
protocol with the optional property, Banana is a fruit which may or may not
implement it, I personally don’t like bananas at all.
var x = Banana()
var y = x as Fruit
if y.createImage != nil
{
x.createImage = theImplementationOfCreateImage
let r = x.createImageOptional( nil )
}
The test on y appears to tell you whether or not the protocol is implemented on
x. Then you can set the property on x inside the block, except you probably
can’t because this is the place you’ve been having issues setting the property
with an error message I can’t make happen. That code works fine for me, and
calls the method (which then crashes because I sent it nil but that’s fine)
There’s probably a deeper issue here. createImage is a property name which
itself implies two methods, one with the same name as the property, the other
with ‘set’ stuffed on the front. Then the implementation of that property is
itself optional. Then you pull all that over to Swift and have to disambiguate
the case where you’re checking for implementation of the property and the case
you’re getting it and checking if it’s set to nil or not and the case you want
to set it to something, possibly back to nil. This may be one of those things
which just doesn’t translate very well.
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Re: Passing a swift function to objective-c
let r = x.createImageOptional( nil ) is of course let r = x.createImage( nil ) I had two properties in my test code and didn’t fix it when I copy/pasted it, sorry. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Passing a swift function to objective-c
On 17 Oct 2014, at 6:13 am, Kevin Meaney k...@yvs.eu.com wrote:
Hi,
I'm beginning to feel this above my pay grade as I can't seem to work it out.
I have a framework in Objective-C. I've been writing some tests for it, and
to make life fun I've been writing the tests in Swift.
I have a property of a class in the objective-c framework declared like so:
@property (nonatomic, copy) CGImageRef (^createImage)(NSDictionary *);
In my tests I'm trying to write a function that I can assign to the property.
In the most basic form the function looks like this, I'm ignoring the passed
in dictionary for the purposes of asking this question:
func createCGImage2(dictionary: [NSObject:AnyObject]) - CGImage {
let jpegURL = NSBundle.mainBundle().URLForResource(myimage,
withExtension:jpg)
let imageSource = CGImageSourceCreateWithURL(jpegURL, nil)!
let theImage = CGImageSourceCreateImageAtIndex(imageSource, 0, nil)
return theImage
}
When I try to set the property with the function I get:
error: cannot convert the expression's type '([NSObject : AnyObject]) -
UnmanagedCGImage!' to type '(([NSObject : AnyObject]!) -
UnmanagedCGImage!)!?'
Now, if I have a function declared like so:
func createCGImageFromDictionary(dictionary: [NSObject:AnyObject]!) -
UnmanagedCGImage!
error: cannot convert the expression's type '([NSObject : AnyObject]!) -
UnmanagedCGImage!' to type '(([NSObject : AnyObject]!) -
UnmanagedCGImage!)!?'
I'm still a long way off. There's an extra () in there and an extra !? at the
end that I really don't know how to interpret. Also I don't know how to
convert the result of CGImageSourceCreateImageAtIndex to a UnmanagedCGImage
as a return value.
I've been through various bits of the documentation, but something isn't
clicking so that I understand how this stuff works so that I can try and
solve it.
Kevin
__
ok this simple test works for me .. I also don’t understand the extra parens
etc in your example. So where does your code differ from the below? Note I set
it both with a public function and a closure, just to see if it works.
I think that’s how you get your Unmanaged object as well, but I’m not entirely
sure. Swift seems to do better with some CoreFoundation types than others.
Note that took far more time messing about with fiddly bits of syntax than I
wish it had, and I’ve only not touched Swift for a week or so.
obj-C bit, Banana.h
@interface Banana : NSObject
@property( nonatomic, copy ) CGImageRef(^createImage)(NSDictionary *dictionary);
@end
swift bit, Orange.swift
public func x( dict : [ NSObject:AnyObject]! ) - UnmanagedCGImageRef!
{
let jpegURL = NSBundle.mainBundle().URLForResource(myimage,
withExtension:jpg)
let imageSource = CGImageSourceCreateWithURL(jpegURL, nil)!
let theImage = CGImageSourceCreateImageAtIndex(imageSource, 0, nil)
let x = Unmanaged.passUnretained(theImage);
x.autorelease()
return x
}
@objc public class Orange
{
var j = Banana()
public func doSomething()
{
j.createImage = x
j.createImage = {
(dict)-UnmanagedCGImageRef in
let jpegURL =
NSBundle.mainBundle().URLForResource(myimage, withExtension:jpg)
let imageSource = CGImageSourceCreateWithURL(jpegURL,
nil)!
let theImage =
CGImageSourceCreateImageAtIndex(imageSource, 0, nil)
let x = Unmanaged.passUnretained(theImage);
x.autorelease()
return x
}
}
}
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