Bamboo Lisp

Embeddable & Hackable Lisp-2 Interpreter

There is a WebAssembly build, you can try it online.

About

Features:

• Lisp-2 (more like Common Lisp or Emacs Lisp)
• Lexical scoping
• < 5000 LoC
• Tail call optimization
• Any C99 compiler should work
• A simple mark-sweep GC
• Writing macro is easy with quasiquote, unquote, and slicing-unquote
• No global state, you can run multiple interpreters in multiple threads
• Exception and try-catch
• Stacktrace for debugging
• Support C-like control flow statements
  • return
  • break
  • continue

Drawbacks:

To keep simplicity, Bamboo Lisp is a VERY SLOW tree-walking interpreter. The performance is similar to other small Lisp interpreters like TinyScheme or very early Emacs Lisp, which is only 1/5 to 1/10 that of modern Python.

Summary:

If you want a TinyScheme-like embeddable lisp intereter but in Lisp-2 flavour, Bamboo Lisp is for you.

Build

Install dependency first, see algds for details.

make mode=release
sudo make install

Usage

After building, you can run the Bamboo Lisp interpreter using:

./bamboo-lisp # To enter the REPL (if applicable)
./bamboo-lisp <filename.lisp> # To run a Lisp file

You can use load to load a lisp script into the interpreter:

(load "my-script.lisp")

Examples

See tests/ for more examples. The tests also serve as documents.

1. Y Combinator

(defun Y (f)
  (funcall
    (lambda (g) (funcall g g))
    (lambda (h)
       (funcall f (lambda args (apply (funcall h h) args))))))

(defun fibo-impl (self)
  (lambda (n)
    (if (<= n 2)
        1
        (+ (funcall self (- n 1)) (funcall self (- n 2))))))

(defvar fibo (Y #'fibo-impl))

(funcall fibo 10)
;; Expected output: 55

2. Macro

(defmacro inc (x)
  `(setq ,x (+ ,x 1)))

(defmacro for (start pred inc . body)
  `(let (,start)
     (while ,pred
       ,@body
       ,inc)))

(for (i 0) (< i 10) (inc i)
  (princ "meow\n"))

;; Expected output:
;; meow
;; meow
;; ... (10 times)