What’s new in Xcode 15

1:52 - Code Completion - PlantSummaryRow

import Foundation
import SwiftUI
import BackyardBirdsData
import LayeredArtworkLibrary

struct PlantSummaryRow: View {
    var plant: Plant
    var body: some View {
        VStack {
            ComposedPlant(plant: plant)
                .padding(4)
                .padding(.bottom, -20)
                .clipShape(.circle)
                .background(.fill.tertiary, in: .circle)
                .padding(.horizontal, 10)
            
            VStack {
                Text(plant.speciesName)
            }
        }
    }
}

3:28 - Code Completion - Latitude & Longitude

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
    if let mostRecent = locations.last?.coordinate {
        logger.debug("Handled coordinate update: \(mostRecent.latitude)")
    }
}

6:18 - BirdIcon Documentation

/// Create the bird icon view.
///
/// The bird icon view is a tailored version of the ``ComposedBird`` view.
///
/// Use this initializer to display an image of a given bird.
///
/// ```swift
/// var bird: Bird
///
/// var body: some View {
///     HStack {
///         BirdIcon(bird: bird)
///             .frame(width: 60, height: 60)
///         Text(bird.speciesName)
///     }
/// }
/// ```
///
/// ![A screenshot of a view containing a bird icon with the bird's species name below it.](birdIcon)

7:37 - CaseDetection Macro

extension TokenSyntax {
    fileprivate var initialUppercased: String {
        let name = self.text
        guard let initial = name.first else {
            return name
        }

        return "\(initial.uppercased())\(name.dropFirst())"
  }
}

public struct CaseDetectionMacro: MemberMacro {
    public static func expansion<
        Declaration: DeclGroupSyntax, Context: MacroExpansionContext
    >(
        of node: AttributeSyntax,
        providingMembersOf declaration: Declaration,
        in context: Context
    ) throws -> [DeclSyntax] {
        declaration.memberBlock.members
            .compactMap { $0.decl.as(EnumCaseDeclSyntax.self) }
            .map { $0.elements.first!.identifier }
            .map { ($0, $0.initialUppercased) }
            .map { original, uppercased in
                """
                var is\(raw: uppercased): Bool {
                    if case .\(raw: original) = self {
                        return true
                    }

                    return false
                }
                """
            }
    }
}

@main
struct EnumHelperPlugin: CompilerPlugin {
    let providingMacros: [Macro.Type] = [
        CaseDetectionMacro.self,
    ]
}

8:07 - Using CaseDetection Macro

@CaseDetection
enum Element {
    case one
    case two
}

var element: Element = .one
if element.isOne {
    // Handle interesting case
}

8:50 - New Preview API

#Preview {
    AppDetailColumn(screen: .account)
        .backyardBirdsDataContainer()
}

#Preview("Placeholder View") {
    AppDetailColumn()
        .backyardBirdsDataContainer()
}

9:22 - UIViewController Preview

#Preview {
    let controller = DetailedMapViewController()

    controller.mapView.camera = MKMapCamera(
        lookingAtCenter: CLLocation(latitude: 37.335_690, longitude: -122.013_330).coordinate,
        fromDistance: 0,
        pitch: 0,
        heading: 0
    )
    return controller
}

17:34 - OSLog

import OSLog

let logger = Logger(subsystem: "BackyardBirdsData", category: "Account")

func login(password: String) -> Error? {
    var error: Error? = nil
    logger.info("Logging in user '\(username)'...")

    // ...

    if let error {
        logger.error("User '\(username)' failed to log in. Error: \(error)")
    } else {
        loggedIn = true
        logger.notice("User '\(username)' logged in successfully.")
    }
    return error
}