Chapter 15. More macros and DSLs
This chapter covers
- A review of Clojure macros
- Anaphoric macros
- Shifting computation to compile time
- Macro generating macros
- Domain-specific languages in Clojure
This final chapter is about what many consider the most powerful feature of Clojure. John McCarthy, the inventor of the Lisp programming language, once said that Lisp is a local maximum in the space of programming languages. Clojure macros make Clojure a programmable programming language because it can do arbitrary code transformations of Clojure code, using Clojure itself. No programming language outside the Lisp family can do this in such a simple way. To reiterate the obvious, this is possible because code is data.
You’ve seen a lot of macros through the course of this book, including in chapter 7, which served as an introduction to the topic. In this section, you’re going to see a lot more but with two new points of focus. The first will be advanced uses of macros, and the second will be the conscious design of a simple domain-specific language.