+;;; Utils
+
+#+common-lisp
+(defmacro while (condition &body body)
+ `(do ()
+ ((not ,condition))
+ ,@body))
+
+(defvar *newline* "
+")
+
+;;; simplify me, please
+(defun concat (&rest strs)
+ (reduce (lambda (s1 s2) (concatenate 'string s1 s2))
+ strs
+ :initial-value ""))
+
+;;; Concatenate a list of strings, with a separator
+(defun join (list separator)
+ (cond
+ ((null list)
+ "")
+ ((null (cdr list))
+ (car list))
+ (t
+ (concat (car list)
+ separator
+ (join (cdr list) separator)))))
+
+(defun join-trailing (list separator)
+ (if (null list)
+ ""
+ (concat (car list) separator (join-trailing (cdr list) separator))))
+
+(defun integer-to-string (x)
+ (if (zerop x)
+ "0"
+ (let ((digits nil))
+ (while (not (= x 0))
+ (push (mod x 10) digits)
+ (setq x (truncate x 10)))
+ (join (mapcar (lambda (d) (string (char "0123456789" d)))
+ digits)
+ ""))))
+
+;;;; Reader
+
+;;; It is a basic Lisp reader. It does not use advanced stuff
+;;; intentionally, because we want to use it to bootstrap a simple
+;;; Lisp. The main entry point is the function `ls-read', which
+;;; accepts a strings as argument and return the Lisp expression.
+(defun make-string-stream (string)
+ (cons string 0))
+
+(defun %peek-char (stream)
+ (if (streamp stream)
+ (peek-char nil stream nil)
+ (and (< (cdr stream) (length (car stream)))
+ (char (car stream) (cdr stream)))))
+
+(defun %read-char (stream)
+ (if (streamp stream)
+ (read-char stream nil)
+ (and (< (cdr stream) (length (car stream)))
+ (prog1 (char (car stream) (cdr stream))
+ (incf (cdr stream))))))
+
+(defun whitespacep (ch)
+ (or (char= ch #\space) (char= ch #\newline) (char= ch #\tab)))
+
+(defun skip-whitespaces (stream)
+ (let (ch)
+ (setq ch (%peek-char stream))
+ (while (and ch (whitespacep ch))
+ (%read-char stream)
+ (setq ch (%peek-char stream)))))
+
+(defun terminalp (ch)
+ (or (null ch) (whitespacep ch) (char= #\) ch) (char= #\( ch)))
+
+(defun read-until (stream func)
+ (let ((string "")
+ (ch))
+ (setq ch (%peek-char stream))
+ (while (not (funcall func ch))
+ (setq string (concat string (string ch)))
+ (%read-char stream)
+ (setq ch (%peek-char stream)))
+ string))
+
+(defun skip-whitespaces-and-comments (stream)
+ (let (ch)
+ (skip-whitespaces stream)
+ (setq ch (%peek-char stream))
+ (while (and ch (eql ch #\;))
+ (read-until stream (lambda (x) (eql x #\newline)))
+ (skip-whitespaces stream)
+ (setq ch (%peek-char stream)))))
+
+(defun %read-list (stream)
+ (skip-whitespaces-and-comments stream)
+ (let ((ch (%peek-char stream)))
+ (cond
+ ((char= ch #\))
+ (%read-char stream)
+ nil)
+ ((char= ch #\.)
+ (%read-char stream)
+ (skip-whitespaces-and-comments stream)
+ (prog1 (ls-read stream)
+ (unless (char= (%read-char stream) #\))
+ (error "')' was expected."))))
+ (t
+ (cons (ls-read stream) (%read-list stream))))))
+
+(defvar *eof* (make-symbol "EOF"))
+(defun ls-read (stream)
+ (skip-whitespaces-and-comments stream)
+ (let ((ch (%peek-char stream)))
+ (cond
+ ((null ch)
+ *eof*)
+ ((char= ch #\()
+ (%read-char stream)
+ (%read-list stream))
+ ((char= ch #\')
+ (%read-char stream)
+ (list 'quote (ls-read stream)))
+ ((char= ch #\`)
+ (%read-char stream)
+ (list 'backquote (ls-read stream)))
+ ((char= ch #\")
+ (%read-char stream)
+ (prog1 (read-until stream (lambda (ch) (char= ch #\")))
+ (%read-char stream)))
+ ((char= ch #\,)
+ (%read-char stream)
+ (if (eql (%peek-char stream) #\@)
+ (progn (%read-char stream) (list 'unquote-splicing (ls-read stream)))
+ (list 'unquote (ls-read stream))))
+ ((char= ch #\#)
+ (%read-char stream)
+ (ecase (%read-char stream)
+ (#\'
+ (list 'function (ls-read stream)))
+ (#\+
+ (let ((feature (read-until stream #'terminalp)))
+ (cond
+ ((string= feature "common-lisp")
+ (ls-read stream);ignore
+ (ls-read stream))
+ ((string= feature "lispstrack")
+ (ls-read stream))
+ (t
+ (error "Unknown reader form.")))))))
+ (t
+ (let ((string (read-until stream #'terminalp)))
+ (if (every #'digit-char-p string)
+ (parse-integer string)
+ (intern (string-upcase string))))))))
+
+(defun ls-read-from-string (string)
+ (ls-read (make-string-stream string)))
+
+
+;;;; Compiler
+
+(let ((counter 0))
+ (defun make-var-binding (symbol)
+ (cons symbol (concat "v" (integer-to-string (incf counter))))))
+
+(let ((counter 0))
+ (defun make-func-binding (symbol)
+ (cons symbol (concat "f" (integer-to-string (incf counter))))))
+
+(defvar *compilations* nil)
+
+(defun ls-compile-block (sexps env fenv)
+ (join-trailing (mapcar (lambda (x)
+ (ls-compile x env fenv))
+ sexps)
+ ";
+"))
+
+(defun extend-env (args env)
+ (append (mapcar #'make-var-binding args) env))
+
+(defparameter *env* '())
+(defparameter *fenv* '())
+
+(defun ls-lookup (symbol env)
+ (let ((binding (assoc symbol env)))
+ (and binding (cdr binding))))
+
+(defun lookup-variable (symbol env)
+ (or (ls-lookup symbol env)
+ (ls-lookup symbol *env*)
+ (error "Undefined variable `~a'" symbol)))
+
+(defun lookup-function (symbol env)
+ (or (ls-lookup symbol env)
+ (ls-lookup symbol *fenv*)
+ (error "Undefined function `~a'" symbol)))
+
+(defmacro define-compilation (name args &body body)
+ ;; Creates a new primitive `name' with parameters args and
+ ;; @body. The body can access to the local environment through the
+ ;; variable ENV.
+ `(push (list ',name (lambda (env fenv ,@args) ,@body))
+ *compilations*))
+
+(defvar *toplevel-compilations*)
+
+(define-compilation if (condition true false)
+ (concat "("
+ (ls-compile condition env fenv)
+ " ? "
+ (ls-compile true env fenv)
+ " : "
+ (ls-compile false env fenv)
+ ")"))
+
+;;; Return the required args of a lambda list
+(defun lambda-list-required-argument (lambda-list)
+ (if (or (null lambda-list) (eq (car lambda-list) '&rest))
+ nil
+ (cons (car lambda-list) (lambda-list-required-argument (cdr lambda-list)))))
+
+(defun lambda-list-rest-argument (lambda-list)
+ (second (member '&rest lambda-list)))
+
+(define-compilation lambda (lambda-list &rest body)
+ (let ((required-arguments (lambda-list-required-argument lambda-list))
+ (rest-argument (lambda-list-rest-argument lambda-list)))
+ (let ((new-env (extend-env (cons rest-argument required-arguments) env)))
+ (concat "(function ("
+ (join (mapcar (lambda (x) (lookup-variable x new-env))
+ required-arguments)
+ ",")
+ "){"
+ *newline*
+ (if rest-argument
+ (concat "var " (lookup-variable rest-argument new-env)
+ " = arguments.slice("
+ (prin1-to-string (length required-arguments))
+ ");"
+ *newline*)
+ "")
+ (concat (ls-compile-block (butlast body) new-env fenv)
+ "return " (ls-compile (car (last body)) new-env fenv) ";")
+ *newline*
+ "})"))))
+
+(define-compilation fsetq (var val)
+ (concat (lookup-function var fenv)
+ " = "
+ (ls-compile val env fenv)))
+
+(define-compilation setq (var val)
+ (concat (lookup-variable var env)
+ " = "
+ (ls-compile val env fenv)))
+
+
+;;; Literals
+
+(defun literal->js (sexp)