This is not the Antlr4 toolset, this is merely the Swift runtime support code. Because this package is a Swift Package Manager package, it can be directly imported into an Xcode project that makes use of Antlr 4.9. This package is currently at version 1.0.0 which aligns with Antlr 4.9. This package will be updated as and when newer releases of Antlr are made available.