Is it possible to create an array of struct instances?

Question

I am trying to create an array of struct instances like this:

let installers: [AnyObject] = [Homebrew(), Ls()]

But I get this error:

value of type 'Homebrew' does not conform to expected element type 'AnyObject'

When I give the array no type, I get an ambiguous type error and that it needs more context.

Is it possible to accomplish what I am trying to do?

I Googled all over, but I can't find anything.

Note that while Adam is correct in the syntax, this is almost always the wrong design. There should be some protocol that both Homebrew and Ls conform to, and you should make your array of that protocol rather than Any. Any breaks Swift's type safety and creates many tricky corner cases and subtle bugs (particularly if generics or Optionals are ever involved). It should be avoided except where absolutely necessary. (The same is equally true of AnyObject.) — Rob Napier
– Rob Napier, Commented Mar 28, 2016 at 17:45

Adam · Accepted Answer · 2016-03-28 17:39:20Z

5

For structs use Any instead of AnyObject.

let installers: [Any] = [Homebrew(), Ls()]

answered Mar 28, 2016 at 17:39

Adam

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Sandeep · Accepted Answer · 2016-03-28 19:08:07Z

2

As Rob proposed above, I have created a simple protocol type InstallerType to help you with this. Instead of having it to conform to Any or AnyObject protocols, conforming it to some specific type would categorise your objects in better way.

extension Homebrew: InstallerType { }
extension Ls: InstallerType { }

let installers: [InstallerType] = [Homebrew(), Ls()]

edited Mar 28, 2016 at 19:08

answered Mar 28, 2016 at 18:49

Sandeep

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Caleb Kleveter · Accepted Answer · 2016-03-28 19:29:21Z

2

Following @RobNapier 's suggestion from his comment, I built a protocol. Because both structs use the id and command constants, I came up with this:

protocol CKInstall {
  var id: String {get}
  var command: [String] {get}
}

Problem solved!

answered Mar 28, 2016 at 19:29

Caleb Kleveter

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