Clojure 1.13 adds support for checked keys
Clojure 1.13 alpha1 introduces support for checked keys, a new feature aimed at improving map access safety. The release also includes other enhancements and refinements to the Clojure language and tooling.
Background
- Clojure is a modern, functional dialect of Lisp that runs on the Java Virtual Machine (JVM), known for its emphasis on immutability, concurrency, and simplicity. It was created by Rich Hickey and is widely used in data engineering, finance, and backend systems.
- This post announces the first alpha release of Clojure 1.13. The headline feature is support for "checked keys" in maps, which adds static (compile-time) validation that only allowed keys are used, catching errors early and improving code safety.
- Additional highlights include a new `sources` directory convention alongside the traditional `src`; JVM 21 support; and updates to the `clojure.java-time` API for working with dates and times in the standard Java time library (java.time).
- This release continues Clojure's gradual evolution under Alex Miller, who took over as lead maintainer after Rich Hickey's retirement in 2020. The 1.13 alpha is currently available for testing and feedback from the community.