Scala 3 moves to release candidate stage

Scala 3 moves to release candidate stage

Type parameters, syntax get attention in planned upgrade to the popular functional language for JVM and JavaScript runtimes

Credit: Kevin (C00)

Scala 3, the planned next version of the object-oriented, functional language with JVM and JavaScript runtimes, has moved to a release candidate stage, with type parameter enhancements and syntax improvements.

The Scala 3 RC, introduced February 17, brings last-minute polishing and cleanups. The user experience was improved and the meta-programming framework enhanced. Scala has both JVM and JavaScript runtimes and is positioned for use in building high-performance systems with access to ecosystems of libraries.

Improvements in Scala 3 RC 1 include type parameters on extensions can be combined with type parameters on the methods themselves. In addition, changes to the import syntax have been made, whereby the wildcard import _ is replaced by * and the renaming operator => is replaced by as.

The syntax of vararg splces has also been changed in patterns and function arguments. The new syntax uses a postfix * instead of : _*, analogous to how a vararg parameter is declared. Beginning with RC 1, Scala no longer generates a function parent for companions of case classes.

Prior to the release candidate, improvements featured in Scala 3 have included compiler optimisations and support for the Scala.js JavaScript implementation of Scala, including support for non-native JS types and better support for JS interoperability.

For pattern bindings, as is allowed in place of @. As of Scala 3.1, the @ syntax will be deprecated. In a syntactic change intended to simplify code, instead of developers using import p.{given _}, they will use import p.given. Furthermore, the metaprogramming API has been made more uniform.

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