I've just faced a strange problem
I have a class called Letter
class Letter
{
init() {}
}
And I have an extension for this class:
extension Letter
{
convenience init(file_path:String) { self = Letter.loadFromFile(file_path)}
class func loadFromFile(file_path:String)->Letter {...}
}
I need to create and init with path to file and when i call Letter(file_path) I need a new object that returned by a func loadFromFile. How to assign in an init method or to return a new object?
//Edit The same problem...
Class functions that return instances of that class seems to be an anti-pattern in Swift. You'll notice that the "with" Objective-C class methods like [NSString stringWithString:@"some other string"] made the transition as "with"-less convenience initializers: NSString(string: "some other string").
Furthermore, you'll need to delegate to a designated initializer from within a convenience initializer.
Also, since you're 1) defining the original class and 2) don't need the convenience initializer scoped differently than the designated initializer, I don't see any reason to place it in an extension.
Putting those together:
class Letter {
init() { … }
convenience init(filePath: String) {
self.init()
loadFromFile(filePath)
}
func loadFromFile(filePath: String) { … }
}
let letter1 = Letter()
letter1.loadFromFile("path1")
let letter2 = Letter(filePath: "path2")
In summary, the analogy for assigning to self in Swift is calling an initializer.
Let me know if this works for you!
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