Apple's documentation is quite clear about how Objective-C initialization methods get converted into Swift intializers:
The “init” prefix gets sliced off and becomes a keyword to indicate that the method is an initializer. For init methods that begin with “initWith,“ the “With” also gets sliced off. The first letter of the selector piece that had “init” or “initWith” split off from it becomes lowercase, and that selector piece is treated as the name of the first argument. The rest of the selector pieces also correspond to argument names.
It is also possible to use factory class methods as initializers; however, there is much less information on how these selector names are mapped to Swift functions:
For consistency and simplicity, Objective-C factory methods get mapped as convenience initializers in Swift. This mapping allows them to be used with the same concise, clear syntax as initializers. For example, whereas in Objective-C you would call this factory method like this:
OBJECTIVE-C
UIColor *color = [UIColor colorWithRed:0.5 green:0.0 blue:0.5 alpha:1.0];
In Swift, you call it like this:
SWIFT
let color = UIColor(red: 0.5, green: 0.0, blue: 0.5, alpha: 1.0)
What are the rules for mapping Objective-C factory methods to Swift initializers?
Copyright Notice：Content Author:「Jayson」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/24214061/how-are-objective-c-factory-methods-converted-into-swift-convenience-initializer