modern-swift

Swift attributes like @frozen and @inlinable control binary stability and performance during library evolution. @frozen locks a struct's layout, while @inlinable exposes implementation across module boundaries, requiring careful coordination with @usableFromInline.

@inlinable in Swift allows the compiler to inline code across modules, whereas @usableFromInline only marks internal declarations as accessible to inlinable code without exposing full source. They interact directly to manage API boundaries and library evolution.

Creating a custom Swift macro involves defining code generation logic using Swift's macro system to reduce boilerplate. This DSL feature allows you to generate repetitive code structures at compile time, improving API expressiveness without runtime overhead.

Use the @backDeployed Swift attribute when introducing new API functionality that needs to run on older OS versions. It deploys the implementation alongside your library, allowing clients to access new features before the platform natively supports them.

@resultBuilder and @propertyWrapper serve distinct roles in Swift DSLs. @resultBuilder constructs complex nested data structures from imperative syntax, while @propertyWrapper encapsulates property access logic, and they can be combined for expressive APIs.

Using #Preview macros incorrectly often stems from misunderstanding their integration with SwiftUI views and macro-driven code generation. You need explicit guidance on macro syntax and execution context to avoid misuses and ensure proper compile-time expansion.