Hands-On Design Patterns with Swift

Components of the strategy pattern

The strategy pattern involves only a few components:

• Context objects, which will have a Strategy member
• Strategy implementations that can be swapped at runtime

Let's attempt to generalize this implementation via protocols.

Strategy is the algorithm that runs the code, and that will be swapped at runtime. At a high level, a strategy is only dependent on its algorithm ReturnType:

protocol Strategy {    associatedtype ReturnType    func run() -> ReturnType}

In practice, this abstraction lacks some definition, as we're missing some information about what we should pass to the algorithm. For the sake of our demonstration, let's rewrite the run() function with a single argument. As we're using generics, this argument ...