Build configuration import testing 관련

HACKING WITH SWIFT

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What's new in Swift?

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Build configuration import testing | Changes in Swift 4.1

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Build configuration import testing

Available from Swift 4.1

Swift 4.1 implemented SE-0075 (apple/swift-evolution), which introduced a new canImport condition that lets us check whether a specific module can be imported when our code is compiled.

This is particularly important for cross-platform code: if you had a Swift file that implemented one behavior on macOS and another on iOS, or if you needed specific functionality for Linux. For example:

#if canImport(SpriteKit)
   // this will be true for iOS, macOS, tvOS, and watchOS
#else
   // this will be true for other platforms, such as Linux
#endif

Previously you would have had to use inclusive or exclusive tests by operating system, like this:

#if !os(Linux)
   // Matches macOS, iOS, watchOS, tvOS, and any other future platforms
#endif

#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
   // Matches only Apple platforms, but needs to be kept up to date as new platforms are added
#endif

The new canImport condition lets us focus on the functionality we care about rather than what platform we're compiling for, thus avoiding a variety of problems.

Other Changes in Swift 4.1

Synthesized Equatable and Hashable | Changes in Swift 4.1

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Synthesized Equatable and Hashable

Key decoding strategies for Codable | Changes in Swift 4.1

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Key decoding strategies for Codable

Conditional conformances | Changes in Swift 4.1

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Conditional conformances

Recursive constraints on associated types | Changes in Swift 4.1

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Recursive constraints on associated types

Target environment testing | Changes in Swift 4.1

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Target environment testing

flatMap is now (partly) compactMap() | Changes in Swift 4.1

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flatMap is now (partly) compactMap()

Download Swift 4.1 playground