1.5. Summary

As you saw, Lisp is a special language, and Clojure is a special Lisp. It’s homoiconic with almost no syntax and has a full macro system. It’s a functional language with first-class functions and immutable data structures, and it has concurrency semantics built into its core. It’s hosted on the extremely mature and performant Java VM, which allows it to offer seamless interoperability with Java code. Being as fast, or nearly as fast as Java, adds another gratifying advantage to Clojure: raw speed.

This combination packs a tremendous productivity punch. The dynamic programming style that Clojure makes possible is well suited to bottom-up design and results in programs that can do a lot more with a lot fewer lines of code. Indeed, when compared with equivalent lines of Ruby code, Clojure code can be two to three times smaller; when compared with Java, it can be nearly five to ten times smaller. Less code means fewer bugs. Clojure code comes close to satisfying the claim of being better, faster, smaller, and cheaper.