Awesome Swift Macros

A hand-curated list of Swift macros. Feel free to contribute!

WWDC23

• Discover Observation in SwiftUI
• Expand on Swift macros
• Write Swift macros

Macros

• Swift Macro Examples

// "Stringify" macro turns the expression into a string.
#stringify(x + y)

// "AddBlocker" complains about addition operations. We emit a warning
// so it doesn't block compilation.
#addBlocker(x * y + z)

// "#URL" macro provides compile time checked URL construction. If the URL is
// malformed an error is emitted. Otherwise a non-optional URL is expanded.
#URL("https://swift.org/")

• swift Power Assert

#powerAssert(max(a, b) == c)
             |   |  |  |  |
             7   4  7  |  12
                       false

• Preview macro (Xcode 15+)

#Preview {
    Button("SwiftUI") {}
}

• SFSymbolsMacro

import SFSymbolsMacro
import SwiftUI

@SFSymbol
enum Symbols: String { ... }

Proposals

• SE-0382: Expression macros
• SE-0389: Attached Macros
• SE-0394 Package Manager Support for Custom Macros