NSSelectorFromString() is still available in Swift, and you should be able to
use the result of that in performSelector, though I’m hesitant to support this
approach as it flies in the face of the safety Swift tries to enforce. I’m
curious about your use case here; are you trying to create some kind of dynamic
proxy for a remote object ala NSXPCConnection?
Dan
> On Dec 10, 2015, at 10:33 AM, Matthew Davies via swift-users
> <swift-users@swift.org> wrote:
>
> Ooh okay. I think that should work for my purposes. Thanks.
>
> Somewhat related to this, how would I then call a method dynamically on an
> instance of the class, after instantiating it?
>
> ---
> class Graph {
> func call(method: String) {
> // Something goes here
> }
>
> func redraw() -> String {
> return "Redraws"
> }
> }
>
> let inst = Graph()
> inst.call("redraw")
> ---
>
>
> Matthew Davies
> Junior Developer, GeoStrategies <http://geostrategies.com/>
> Director of Photography, OffBlock Films <http://offblockfilms.com/>
> 209-225-3246 <tel:209-225.3246> | 209-202-3284 <tel:209-202-3284> |
> daviesg...@gmail.com <mailto:daviesg...@gmail.com> | daviesgeek.com
> <https://daviesgeek.com/>
> <http://facebook.com/daviesgeek> <http://us.linkedin.com/in/daviesgeek>
> <http://twitter.com/daviesgeek> <http://daviesgeek.com/feed.xml>
> <http://github.com/daviesgeek>
>
> On Thu, Dec 10, 2015 at 10:18 AM, Daniel Dunbar <daniel_dun...@apple.com
> <mailto:daniel_dun...@apple.com>> wrote:
> Note that you can define a protocol which will allow your framework to
> instantiate the type, and to call methods on instances of that type. If you
> can structure your code in this fashion, it can be very elegant in that it
> doesn't require factory functions and it is type safe.
>
> For example:
> --
> struct GraphableDescription { }
>
> protocol Graphable {
> /// Construct a graphable item from a description.
> init(description: GraphableDescription)
>
> func graph()
> }
>
> // Example framework method.
> func graphItem(description: GraphableDescription, graphable: Graphable.Type) {
> // Instantiate the graphable.
> let item = graphable.init(description: description)
>
> // Graph it.
> item.graph()
> }
>
> // Example Graphable client.
> struct Circle: Graphable {
> init(description: GraphableDescription) { }
>
> func graph() { }
> }
>
> // Example framework client.
> func foo() {
> graphItem(GraphableDescription(), graphable: Circle.self)
> }
> --
>
> - Daniel
>
>> On Dec 10, 2015, at 9:59 AM, Matthew Davies via swift-users
>> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote:
>>
>> I don't really like the idea of a factory function, but unfortunately that
>> might be the only way to do it :( However, due to my specific use case, I
>> don't think a factory function will work. I'm working on a framework that
>> will need to both instantiate the class from a string (or class type) and
>> call methods dynamically on it. Which, I'm not sure I can do in the build
>> tools that are provided in the open source package. Foundation hasn't been
>> fully implemented and is missing a lot of the methods that would allow this
>> to work.
>>
>> @Jens thanks for that blog post. I'll have to make sure I check back to see
>> what his solution is for it.
>>
>>
>>
>>
>> Matthew Davies
>> Junior Developer, GeoStrategies <http://geostrategies.com/>
>> Director of Photography, OffBlock Films <http://offblockfilms.com/>
>> 209-225-3246 <tel:209-225.3246> | 209-202-3284 <tel:209-202-3284> |
>> daviesg...@gmail.com <mailto:daviesg...@gmail.com> | daviesgeek.com
>> <https://daviesgeek.com/>
>> <http://facebook.com/daviesgeek> <http://us.linkedin.com/in/daviesgeek>
>> <http://twitter.com/daviesgeek> <http://daviesgeek.com/feed.xml>
>> <http://github.com/daviesgeek>
>>
>> On Thu, Dec 10, 2015 at 9:30 AM, Jan Neumüller <swift-users@swift.org
>> <mailto:swift-users@swift.org>> wrote:
>> Please no factory madness in Swift. This stuff is bad enough in Java - don’t
>> infect Swift with it.
>>
>> Jan
>>
>>> On 10.12.2015, at 18:23, Jens Alfke via swift-users <swift-users@swift.org
>>> <mailto:swift-users@swift.org>> wrote:
>>>
>>>
>>>> On Dec 10, 2015, at 7:26 AM, Harlan Haskins via swift-users
>>>> <swift-users@swift.org <mailto:swift-users@swift.org>> wrote:
>>>>
>>>> IIRC this isn’t possible because there’s no Runtime to query for
>>>> classnames (it’s inherently unsafe anyway).
>>>
>>> It’s not unsafe if you specify a base class/protocol that the loaded class
>>> must conform to.
>>>
>>>> You might want to look into a better way of doing that you’re trying to do.
>>>
>>> I disagree with “a better way” — “a workaround” is how I’d rephrase it.
>>> This kind of dynamism is often the best tool for the job, and a lot of
>>> Cocoa developers are frustrated by its absence in Swift. For example,
>>> there’s a series of blog posts from earlier this year by the highly
>>> respected Brent Simmons [NetNewsWire, MarsEdit, Glassboard, etc., currently
>>> at Omni]:
>>> http://inessential.com/swiftdiary <http://inessential.com/swiftdiary>
>>>
>>> http://inessential.com/2015/07/20/swift_diary_1_class_or_struct_from_str
>>> <http://inessential.com/2015/07/20/swift_diary_1_class_or_struct_from_str>
>>>
>>> The workaround I’d suggest is a factory function that contains a switch
>>> statement that matches class names and returns newly initialized instances.
>>>
>>> —Jens
>>>
>>> _______________________________________________
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>>> swift-users@swift.org <mailto:swift-users@swift.org>
>>> https://lists.swift.org/mailman/listinfo/swift-users
>>> <https://lists.swift.org/mailman/listinfo/swift-users>
>>
>>
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