Matching optional enums against non-optionals 관련

HACKING WITH SWIFT

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What's new in Swift?

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Matching optional enums against non-optionals | Changes in Swift 5.1

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Matching optional enums against non-optionals

Available from Swift 5.1

Swift has always been smart enough to handle switch/case pattern matching between optionals and non-optionals for strings and integers, but before Swift 5.1 that wasn’t extended to enums.

Well, in Swift 5.1 we can now use switch/case pattern matching to match optional enums with non-optionals, like this:

enum BuildStatus {
    case starting
    case inProgress
    case complete
}

let status: BuildStatus? = .inProgress

switch status {
case .inProgress:
    print("Build is starting…")
case .complete:
    print("Build is complete!")
default:
    print("Some other build status")
}

Swift is able to compare the optional enum directly with the non-optional cases, so that code will print “Build is starting…”

Other Changes in Swift 5.1

Improvements to synthesized memberwise initializers | Changes in Swift 5.1

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Improvements to synthesized memberwise initializers

Implicit returns from single-expression functions | Changes in Swift 5.1

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Implicit returns from single-expression functions

Universal Self | Changes in Swift 5.1

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Universal Self

Opaque return types | Changes in Swift 5.1

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Opaque return types

Static and class subscripts | Changes in Swift 5.1

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Static and class subscripts

Warnings for ambiguous none cases | Changes in Swift 5.1

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Warnings for ambiguous none cases

Ordered collection diffing | Changes in Swift 5.1

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Ordered collection diffing

Creating uninitialized arrays | Changes in Swift 5.1

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Creating uninitialized arrays

Download Swift 5.1 playground