From the course: Swift 5: Protocol-Oriented Programming

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Placeholder types in protocols

Placeholder types in protocols

From the course: Swift 5: Protocol-Oriented Programming

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Placeholder types in protocols

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- So far, we've looked at the benefits of generic types and functions and how to use them. How 'about protocols? I've gone ahead and created the new playground page called Associated Types. I added the definition of the Taggable Protocol. You can find the project in the Exercise Five, chapter three, o three o four, begin further. The Taggable Protocol defines requirements for any tag that can hold binary data and uses a tag to identify it. Now, wouldn't it be great to create a protocol that's not restricted to the data type? Swift allows us to declare a place for the types in protocols. Let's see how. I declare an associated type next. The associated type key word lets us define the place for the name for a type within a protocol. I'm going to call it Content. The actual type is unknown until a confirming type provides it. Next, I replace the type of the data property with a place order type. And finally, let's…

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