Swift Any Array not accessing Struct Methods - arrays

Question

So, I have the following code in Swift 2:
struct IntToken {
var value:Int
init(val:Int) {
self.value = val
}
mutating func add(val:IntToken) {
self.value += val.value
}
}
var table = [Any]()
table.append(IntToken(val:3))
table.append(IntToken(val:4))
table[0].add(table[1])
This gives me the following error
Playground execution failed: /var/folders/jx/bhltcyc90117d2wx_r82p4fr0000gn/T/./lldb/73237/playground71.swift:22:6: error: value of type 'Any' (aka 'protocol<>') has no member 'add'
table[0].add(table[1])
~~~~~^~~ ~~~
The issue is, I am trying to create an Array, that will contain different type of objects, not just IntToken's, but I also want to be able to access the elements of that array and use their methods on one another. Whenever I try to use the Any array, however, it doesn't allow me to do this, because it's reading the accessed struct instance as an any type.
What's a good way to accomplish what I am trying to do?

Answer 1

Starting with your original struct:
struct IntToken {
var value:Int
init(val:Int) {
self.value = val
}
mutating func add(val:IntToken) {
self.value += val.value
}
}
Do like this:
var table = [Any]()
table.append(IntToken(val:3))
table.append(IntToken(val:4))
var it = table[0] as! IntToken // take it out with cast and var ref
it.add(table[1] as! IntToken) // add with cast; `it` is now IntToken(val:7)
table[0] = it // put it back in (if you want to)

Answer 2

i slightly modified matt's answer (accepted answer) to show how to avoid crash in case some table element has other type as IntToken.
var table:[Any] = []
table.append(IntToken(val:3))
table.append(IntToken(val:4))
if let it0 = table[0] as? IntToken,
let it1 = table[1] as? IntToken {
var it0 = it0
it0.add(it1)
table[0] = it0
}
print(table) // [IntToken(value: 7), IntToken(value: 4)]
I prefer to modify your IntToken
struct IntToken {
var value:Int
func add1(token: IntToken)->IntToken {
var token = token
token.value += value
return token
}
}
and remove any 'mutating' function from it. Now the original code snippet could be modified to 'more functional' and easy to understand version
var table = [Any]()
table.append(IntToken(value:3))
table.append(IntToken(value:4))
if let it1 = table[1] as? IntToken,
let v = (table[0] as? IntToken)?.add1(it1) {
table[0] = v
}
print(table) // [IntToken(value: 7), IntToken(value: 4)]