DougGregor

A Possible Vision for Macros in Swift

As Swift evolves, it gains new language features and capabilities. There are different categories of features: some fill in gaps, taking existing syntax that is not permitted and giving it a semantics that fit well with the existing language, with features like conditional conformance or allowing existential values for protocols with Self or associated type requirements. Others introduce new capabilities or paradigms to the language, such as the addition of concurrency or comprehensive reflection.

There is another large category of language features that provide syntactic sugar to eliminate common boilerplate, taking something that can be written out in long-form and making it more concise. Such features don't technically add any expressive power to the language, because you can always write the long-form version, but their effect can be transformational if it enables use cases that would otherwise have been unwieldy. The synthesis of Codable conformances, for ex

steipete

class FirebaseCoordinator {
    static let shared = FirebaseCoordinator()
    static let initialize: Void = {
        /// We modify Google Firebase (and eventually Analytics) to load the mac-specific plist at runtime.
        /// Google enforces that we have a file named "GoogleService-Info.plist" in the app resources.
        /// This is unfortunate since we need two different files based on iOS and Mac version
        /// One solution is a custom build step that copies in the correct file:
        /// https://stackoverflow.com/questions/37615405/use-different-googleservice-info-plist-for-different-build-schemes
        /// However, this is basically impossible since Catalyst doesn't set any custom build variables, so detection is extremely difficult.
        /// We swizzle to modify the loading times.

mikeash

import Cocoa

enum CoroutineState {
    case Fresh, Running, Blocked, Canceled, Done
}

struct CoroutineCancellation: ErrorType {}

class CoroutineImpl<InputType, YieldType> {
    let body: (yield: YieldType throws -> InputType) throws -> Void