BODOL

This is my language experiment.

Preliminary goals which may or may not be possible to combine:

• Pure functional language.
• Homoiconic in the Lisp tradition.
• Built on the traditional Lisp primitives.
• Hindley-Milner flavoured type system.
• Currying function calls.
• Pattern matching.

This is a work in progress. Don't expect it to even run its own test suite.

Inspiration

Clojure is great, but sometimes I miss static typing. Haskell is great, but sometimes I miss Lisp's elegantly simple syntax. Shen is a splendid compromise, but I found myself wishing it came with Haskell's uncompromising purity and Standard ML's straightforward type system. BODOL is my attempt at crossbreeding the three, with Shen obviously the major influence.

A Taste of BODOL

Functional hello world:

(ƒfactorial0->1n->(*n(factorial(-n1))))(ƒfibonacci0->01->1n->(+(fibonacci(-n1))(fibonacci(-n2))))

More advanced pattern matching:

(ƒmapf()->()f(head.tail)->(cons(fhead)(mapftail)))(='(234)(map(λa->(+a1))'(123))))

Currying:

(ƒtripletabc->(listabc))(defineone-and(triplet1))(defineone-and-two-and(one-and2))(='(123)(one-and-two-and3))

Take a look at the theoretically comprehensivetest suite for examples of all the currently defined language features.

Test Drive

The BODOL prototype interpreter is written in Clojure, so you'll need to install Leiningen in order to run it. Optionally, you may also want to installrlwrap for a better line editing experience. Once that's done, check out the BODOL repo, cd over there and type:

$ ./repl
BODOL version 0.0.0
You are in a maze of twisty little passages, all alike.
→→

If you're discouraged by the curious absence of λ and ƒ on your keyboard, you can substitute Clojure's fn and defn or Common Lisp's lambda and defun respectively.

If you're using Emacs, I find this helps:

;; Keybindings for λ and ƒ(global-set-key(kbd"M-l")(lambda()(interactive)(insert"\u03bb")));lambda(global-set-key(kbd"M-f")(lambda()(interactive)(insert"\u0192")));function;; Launch the BODOL REPL in an inferior-lisp buffer(defunbodol-repl()(interactive)(run-lisp"<path to your BODOL repo>/repl"))