[swift-users] Instantiate Swift class from string

[Jan Neumüller]

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 at swift.org> wrote:
> 
> 
>> On Dec 10, 2015, at 7:26 AM, Harlan Haskins via swift-users <swift-users at swift.org <mailto:swift-users at 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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