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iOS Intermediate Swift 2 Extensions and Protocols Protocol Conformance Through Extensions

Cody Adkins
Cody Adkins
7,260 Points

Why did we not have to write the Name and ID, to conform to User type in the extension of User type?

Does Swift already know that those properties are in the User type? So we do not have to explicitly write it out...

1 Answer

Steven Deutsch
Steven Deutsch
21,046 Points

Hey Cody Adkins,

You do not need to specify the name and ID in the User type's extension for a few reasons. Mainly, because these two properties are not specified in the PrettyPrintable protocol that you are conforming User to. The purpose of this extension is to achieve protocol conformance. You do this by implementing the properties and methods that the protocol specifies.

Remember that extensions are just a way to add additional functionality to a type in Swift. The User type already has the name and ID properties listed inside of them. Therefore, redeclaring them in an extension would be repetitive and trigger a compiler error for the invalid redeclaration.

Good Luck