Explain the concept of module linking in Swift and its significance in application development.

In Swift, module linking is the process of combining compiled code parts (modules) into a single application or library. A module in Swift is a separate block of code, usually corresponding to a single framework or package, which is compiled separately.

Linking is important because it allows:

• To divide code into independent parts for easier development and reuse.
• To reduce compilation time by only compiling changed modules.
• To ensure encapsulation and access control between modules.

During the development of a Swift application, the compiler first compiles each module into object code, then links them, resolving dependencies between them. This allows creating scalable and maintainable projects where different teams can work on different modules.

Example: if you have a business logic module and a UI module, they can be compiled separately and then linked into a single application.