Improved implicit member syntax

Paul Hudson      @twostraws

SE-0287 improves Swift’s ability to use implicit member expressions, so rather than just having support for exactly one single static member you can make chains of them.

Swift has always had the ability to use implicit member syntax for simple expressions, for example if you wanted to color some text in SwiftUI you could use .red rather than Color.red:

import SwiftUI

struct ContentView1: View {
    var body: some View {
        Text("You're not my supervisor!")
            .foregroundColor(.red)
    }
}

Prior to Swift 5.4 this did not work with more complex expressions. For example, if you wanted your red color to be slightly transparent you would need to write this:

struct ContentView2: View {
    var body: some View {
        Text("You're not my supervisor!")
            .foregroundColor(Color.red.opacity(0.5))
    }
}

From Swift 5.4 onwards the compiler is able to understand multiple chained members, meaning that the Color type can be inferred:

struct ContentView3: View {
    var body: some View {
        Text("You're not my supervisor!")
            .foregroundColor(.red.opacity(0.5))
    }
}

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Other changes in Swift 5.4…

• Multiple variadic parameters in functions
• Local functions now support overloading
• Creating variables that call a function of the same name
• Result builders
• Property wrappers are now supported for local variables
• Packages can now declare executable targets

Download all Swift 5.4 changes as a playground Link to Swift 5.4 changes

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