filter.swift

protocol Base {
    var name:String { get }
    func doSomething() -> String
}
struct A : Base {
    var name:String { return "Filter A" }
    func doSomething() -> String { return "do A" }
}
struct B : Base {
    var name:String { return "Filter B" }
    func doSomething() -> String { return "do B" }
}
struct C : Base {
    var name:String { return "Filter C" }
    func doSomething() -> String { return "do C" }
}

let filters:[Base] = [
    A(), B(), C()
]

if let filter = filters.filter({ $0.name == "Filter A" }).first {
    let result = filter.doSomething()
}