+(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) ";" *newline*
+ "for (var i = arguments.length-1; i>="
+ (integer-to-string (length required-arguments))
+ "; i--)" *newline*
+ (lookup-variable rest-argument new-env) " = "
+ "{car: arguments[i], cdr: " (lookup-variable rest-argument new-env) "};"
+ *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)
+ (cond
+ ((null sexp) "undefined")
+ ((integerp sexp) (integer-to-string sexp))
+ ((stringp sexp) (concat "\"" sexp "\""))
+ ((symbolp sexp) (concat "{name: \"" (symbol-name sexp) "\"}"))
+ ((consp sexp) (concat "{car: "
+ (literal->js (car sexp))
+ ", cdr: "
+ (literal->js (cdr sexp)) "}"))))
+
+(let ((counter 0))
+ (defun literal (form)
+ (let ((var (concat "l" (integer-to-string (incf counter)))))
+ (push (concat "var " var " = " (literal->js form)) *toplevel-compilations*)
+ var)))
+
+(define-compilation quote (sexp)
+ (literal sexp))
+
+(define-compilation debug (form)
+ (concat "console.log(" (ls-compile form env fenv) ")"))
+
+(define-compilation while (pred &rest body)
+ (concat "(function(){ while("
+ (ls-compile pred env fenv)
+ "){"
+ (ls-compile-block body env fenv)
+ "}})()"))
+
+(define-compilation function (x)
+ (cond
+ ((and (listp x) (eq (car x) 'lambda))
+ (ls-compile x env fenv))
+ ((symbolp x)
+ (lookup-function x fenv))))
+
+#+common-lisp
+(defmacro eval-when-compile (&body body)
+ `(eval-when (:compile-toplevel :execute)
+ ,@body))
+
+(defvar *eval-when-compilations*)
+(define-compilation eval-when-compile (&rest body)
+ (eval (cons 'progn body))
+ nil)
+
+(defmacro define-transformation (name args form)
+ `(define-compilation ,name ,args
+ (ls-compile ,form env fenv)))
+
+(define-transformation progn (&rest body)
+ `((lambda () ,@body)))
+
+(define-transformation let (bindings &rest body)
+ `((lambda ,(mapcar 'car bindings) ,@body)
+ ,@(mapcar 'cadr bindings)))
+
+;;; A little backquote implementation without optimizations of any
+;;; kind for lispstrack.
+(defun backquote-expand-1 (form)
+ (cond
+ ((symbolp form)
+ (list 'quote form))
+ ((atom form)
+ form)
+ ((eq (car form) 'unquote)
+ (car form))
+ ((eq (car form) 'backquote)
+ (backquote-expand-1 (backquote-expand-1 (cadr form))))
+ (t
+ (cons 'append
+ (mapcar (lambda (s)
+ (cond
+ ((and (listp s) (eq (car s) 'unquote))
+ (list 'list (cadr s)))
+ ((and (listp s) (eq (car s) 'unquote-splicing))
+ (cadr s))
+ (t
+ (list 'list (backquote-expand-1 s)))))
+ form)))))
+
+(defun backquote-expand (form)
+ (if (and (listp form) (eq (car form) 'backquote))
+ (backquote-expand-1 (cadr form))
+ form))
+
+(defmacro backquote (form)
+ (backquote-expand-1 form))
+
+(define-transformation backquote (form)
+ (backquote-expand-1 form))
+
+;;; Primitives
+
+(define-compilation + (x y)
+ (concat "((" (ls-compile x env fenv) ") + (" (ls-compile y env fenv) "))"))
+
+(define-compilation - (x y)
+ (concat "((" (ls-compile x env fenv) ") - (" (ls-compile y env fenv) "))"))
+
+(define-compilation * (x y)
+ (concat "((" (ls-compile x env fenv) ") * (" (ls-compile y env fenv) "))"))
+
+(define-compilation / (x y)
+ (concat "((" (ls-compile x env fenv) ") / (" (ls-compile y env fenv) "))"))
+
+(define-compilation = (x y)
+ (concat "((" (ls-compile x env fenv) ") == (" (ls-compile y env fenv) "))"))
+
+(define-compilation null (x)
+ (concat "(" (ls-compile x env fenv) "== undefined)"))
+
+(define-compilation cons (x y)
+ (concat "{car: " (ls-compile x env fenv) ", cdr: " (ls-compile y env fenv) "}"))
+
+(define-compilation car (x)
+ (concat "(" (ls-compile x env fenv) ").car"))
+
+(define-compilation cdr (x)
+ (concat "(" (ls-compile x env fenv) ").cdr"))
+
+(define-compilation make-symbol (name)
+ (concat "{name: " (ls-compile name env fenv) "}"))
+
+(define-compilation symbol-name (x)
+ (concat "(" (ls-compile x env fenv) ").name"))
+
+(define-compilation eq (x y)
+ (concat "(" (ls-compile x env fenv) " === " (ls-compile y env fenv) ")"))
+
+(define-compilation code-char (x)
+ (concat "String.fromCharCode( " (ls-compile x env fenv) ")"))
+
+(define-compilation char (string index)
+ (concat "("
+ (ls-compile string env fenv)
+ ").charCodeAt("
+ (ls-compile index env fenv)
+ ")"))
+
+(define-compilation concat-two (string1 string2)
+ (concat "("
+ (ls-compile string1 env fenv)
+ ").concat("
+ (ls-compile string2 env fenv)
+ ")"))
+
+(define-compilation funcall (func &rest args)
+ (concat "("
+ (ls-compile func env fenv)
+ ")("
+ (join (mapcar (lambda (x)
+ (ls-compile x env fenv))
+ args)
+ ", ")
+ ")"))
+
+(define-compilation new ()
+ "{}")
+
+(define-compilation get (object key)
+ (concat "(" (ls-compile object env fenv) ")[" (ls-compile key env fenv) "]"))
+
+(define-compilation set (object key value)
+ (concat "(" (ls-compile object env fenv) ")[" (ls-compile key env fenv) "]")
+ " = " (ls-compile value env fenv))
+
+
+
+(defun %compile-defvar (name)
+ (push (make-var-binding name) *env*)
+ (push (concat "var " (lookup-variable name *env*)) *toplevel-compilations*))
+
+(defun %compile-defun (name)
+ (push (make-func-binding name) *fenv*)
+ (push (concat "var " (lookup-variable name *fenv*)) *toplevel-compilations*))
+
+(defun %compile-defmacro (name lambda)
+ (push (cons name (cons 'macro lambda)) *fenv*))
+
+(defun ls-macroexpand-1 (form &optional env fenv)
+ (let ((function (cdr (assoc (car form) *fenv*))))
+ (if (and (listp function) (eq (car function) 'macro))
+ (apply (eval (cdr function)) (cdr form))
+ form)))
+
+(defun compile-funcall (function args env fenv)
+ (cond
+ ((symbolp function)
+ (concat (lookup-function function fenv)
+ "("
+ (join (mapcar (lambda (x) (ls-compile x env fenv)) args)
+ ", ")
+ ")"))
+ ((and (listp function) (eq (car function) 'lambda))
+ (concat "(" (ls-compile function env fenv) ")("
+ (join (mapcar (lambda (x) (ls-compile x env fenv)) args)
+ ", ")
+ ")"))
+ (t
+ (error "Invalid function designator ~a." function))))
+
+(defun ls-compile (sexp &optional env fenv)
+ (cond
+ ((symbolp sexp) (lookup-variable sexp env))
+ ((integerp sexp) (integer-to-string sexp))
+ ((stringp sexp) (concat "\"" sexp "\""))
+ ((listp sexp)
+ (let ((sexp (ls-macroexpand-1 sexp env fenv)))
+ (let ((compiler-func (second (assoc (car sexp) *compilations*))))
+ (if compiler-func
+ (apply compiler-func env fenv (cdr sexp))
+ (compile-funcall (car sexp) (cdr sexp) env fenv)))))))