Skaro

A silly robots game, implemented in a number of programming languages: Scheme (Chicken), Racket, Clojure, and Emacs Lisp.

In each case I tried to stick with an idiomatic style for each language. I also limited myself to using no third-party libraries, (even though in some cases it would have resulted in neater code) in order to better capture the spirit of the language.

The Scheme version is very imperative, but the Racket version is functional because Racket has much better support for immutable data structures. The Clojure version obviously is very functional and uses destructuring heavily. The Emacs Lisp version is the most imperative of all, but it includes a full textual buffer-based user interface that is a lot more sophisticated than the read/print interface used by the other versions. The OCaml version is a fairly literal translation of the Clojure version, but using records.

No attempt is made to compare performance across these implementations. Performance tuning and measurement is a very nuanced task that is not possible to do well on a runtime you've spent merely a matter of days on.

Current LOC comparison:

Scheme: 79
Racket: 80
Clojure: 59
Emacs Lisp: 84
OCaml: 77

A more thorough write-up is on my blog.

Other implementations

• PicoLisp
• Forth
• Common Lisp