Swift Auto Builder

Swift Auto Builder is a macro that generates builder classes that implement the Builder design pattern for your types.

The macro currently supports structs and enums. Support for classes is planned.

How to Add Swift Auto Builder as a Dependency

Xcode Project

Go to File -> "Add Package Dependencies...". In the search box on the top right where it says "Search or Enter Package URL" and enter https://github.com/justinrschmidt/SwiftAutoBuilder. Select the "swiftautobuilder" package from the list and click "Add Package". Import Auto Builder by adding import AutoBuilder.

Swift Package Manager

In your package, add .package(url: "https://github.com/justinrschmidt/SwiftAutoBuilder", from: "0.1.1-beta-2") to your package's dependencies array. Then add .product(name: "AutoBuilder", package: "SwiftAutoBuilder") to the dependencies array of any target that uses Auto Builder. Import Auto Builder by adding import AutoBuilder.

How to Use Auto Builder

As an example, the following struct:

@Buildable
struct Foo {
  var a: Int
  var b: Int
}

Can be created with a builder:

let foo = try Foo.Builder()
  .set(a: 1)
  .set(b: 2)
  .build()

// prints: "1, 2"
print("\(foo.a), \(foo.b)")

If your type's properties are also using @Buildable, then you can chain those "nested" builders together:

@Buildable
struct Foo {
  var a: Int
  var b: Int
}

@Buildable
struct Bar {
  var foo: Foo
}

let barBuilder = Bar.Builder()
barBuilder.foo.builder
  .set(a: 1)
  .set(b: 2)
let bar = try barBuilder.build()

// prints: "1, 2"
print("\(bar.foo.a), \(bar.foo.b)")

@Buildable also generates helper functions in the builder class that allow you to add elements to Arrays, Dictionarys, and Sets:

@Buildable
struct Foo {
  var a: [Int]
  var b: [String:Int]
  var c: Set<Int>
}

let foo = try Foo.Builder()
  .appendTo(a: 1) // Append element to Array
  .insertInto(b: 2, forKey: "2") // Add key-value pair to Dictionary
  .insertInto(c: 3) // Insert element into Set
  .build()

// prints: "1, 2, 3"
print("\(foo.a.first!), \(foo.b["2"]!), \(foo.c.first!)")