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SwiftUsing brings to Swift theusing feature from Jai,Jonathan Blow's programming language. It usesSwiftSyntax to code generate the required code.

To learn more aboutSwiftUsing development you can check out the blog postImplementing using in Swift with SwiftSyntax.

using helps withStruct composition.

It allows you to recover the nice syntax from class inheritance when you usestructs instead.

structUser{varname:Stringvarage:Int}structFriend{    // usingletuser:UservarfriendshipDate:Date}friend.name // with class inheritancefriend.user.name // with struct composition :(friend.name // with struct composition and using !!

1. Annotate a property with a comment:// using

struct Friend{...    // using          <- add this commentletuser:User...}

Note that both types must be in the same file. See Known limitations below.

2. Run the command line tool

⚠️ This command will overwrite the original file so make sure you have a copy or you're using a versioning control system like Git in case something goes wrong.

swiftusing/path/to/file

Clone the repo and runmake install.

• Basic declaration syntaxlet/var identifier: Type
• Reliant on comments (is just an external tool after all)
• Single file, using types must be in the same file.
• No collision detection, the compiler will error instead.

## Acknowledgements

• Jonathan Blow for sharing the development of Jai
• pointfree for the informative and inspiring videos
• Swift AST Explorer
• swift-syntax obviously!
• Yaap
• PackageBuilder

SwiftUsing is developed completely in the open, and your contributions are more than welcome.

This project does not come with GitHub Issues-based support, and users are instead encouraged to become active participants in its continued development — by fixing any bugs that they encounter, or improving the documentation wherever it’s found to be lacking.

If you wish to make a change,open a Pull Request — even if it just contains a draft of the changes you’re planning, or a test that reproduces an issue — and we can discuss it further from there.

Alejandro Martinez |http://alejandromp.com |@alexito4