Staying true to its plan, the recently announced Swift 3.1 is source compatible with Swift 3.0. Still, it includes a number of changes to the language, the standard library, and improved Linux implementation.<\/b>
Staying true to its plan, the recently announced Swift 3.1 is source compatible with Swift 3.0. Still, it includes a number of changes to the language, the standard library, and improved Linux implementation.
On the language front, two new members have been added to the Sequence protocol: drop(while:) and prefix(while:). They return the subsequence obtained by dropping or including the initial elements of a sequence while a given predicate is true. So, if you have a sequence s , you can take its n-th to m-th subsequence by executing:
Swift 3.1 also adds a number of conversion initializers for all numeric types, including Int , Float , and Double types, which either produce a correct result, or return nil. Failable initializers, as they are called, are meant to better address conversion from loosely typed data, such as those represented in a JSON format. All numeric types have thus a new initializer that uses the exactly keyword, e.g.,
Having initializers that can fail has been preferred to initializers that can throw an exception based on community feedback .
Not mentioned in the official announcement, but documented in the updated Apple\u2019s guide to Swift 3.1 , type extension can now include a generic where clause:
Previously, the where clause could only be used to constrain a generic to a given protocol, which could lead to introducing ad-hoc protocol only used to specify that constraint:
As a final note about the language, Swift 3.1 extends the @available attribute so it allows to express availability by Swift version , whereas it previously only allowed to specify availability by language and platform:
This relieves programmers from using conditional compilation to juggle with alternate versions of functions, declarations, etc.
The Linux implementation of Swift has seen improvements to many existing classes, including NSDecimal , URLSession , NSArray , NSData , improved JSON serialization performance, and many others.
Finally, the Swift Package Manager has got a number of awaited features, such as:
Swift 3.1 is available through Xcode 8.3 on macOS, a binary distribution for Ubuntu , and as source code for other platforms from GitHub .<\/p>\n