;-*-Scheme-*-

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; LEXICAL STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Bind vars in body
(defmacro let (bindings &rest body)
  `((lambda :inline-only #t ,(apply first bindings) ,@body)
    ,@(apply second bindings)))

;; Let, but recursive, allowing you to define variables in terms of others.
(defmacro let* (bindings &rest body)
  (if (null? bindings)
    `(begin ,@body)
    `((lambda :inline-only #t (,(caar bindings))
        (let* ,(cdr bindings) ,@body))
      ,(car (cdar bindings))
      )
    )
  )

;; Backup some values, and restore after executing body.
;; Non-dynamic (nonlocal jumps out of body will skip restore)
(defmacro protect (defs &rest body)
  (if (null? defs)
    ;; nothing to backup, just insert body (base case)
    `(begin ,@body)

    ;; a unique name for the thing we are backing up
    (with-gensyms (backup)
                  ;; store the original value of the first def in backup
                  `(let ((,backup ,(first defs)))
                     ;; backup any other things which need backing up
                     (protect ,(cdr defs)
                              ;; execute the body
                              ,@body
                              )
                     ;; restore the first thing
                     (set! ,(first defs) ,backup)
                     )
                  )
    )
  )


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; DEFINE STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;; Define a new function
(defmacro defun (name bindings &rest body)
  (if (and
        (> (length body) 1)      ;; more than one thing in function
        (string? (first body))   ;; first thing is a string
        )
    ;; then it's a docstring and we ignore it.
    `(define ,name (lambda :name ,name ,bindings ,@(cdr body)))
    ;; otherwise don't ignore it.
    `(define ,name (lambda :name ,name ,bindings ,@body))
    )
  )

;; Define a new function, but only if we're debugging.
;; TODO - should place the function in the debug segment!
(defmacro defun-debug (name &rest args)
  `(if *debug-segment*
     (defun ,name ,@args) ;; debug data is loaded, define function in symbol table
     (define ,name nothing) ;; function not loaded, set function to the nothing function.
     )
  )

;; By default, recursive functions don't work because the compiler doesn't
;; know the return type of a function until after the function is fully defined.
;; To get around this, this macro allows you to define a function + give a return type.
;; it simply forward declares the function with the given return, then defines the function as normal
;; if you got the return type wrong, the function definition conflicts with the forward dec
;; and throws an error.
(defmacro defun-recursive (name bindings return-type &rest body)
  `(begin
     (defun-extern ,name ,bindings ,return-type)
     (define ,name (lambda :name ,name ,bindings 
                     ;; omit the doc-string if needed
                     ,@(if (and (> (length body) 1) (string? (first body)))
                         (cdr body)
                         body
                         )
                     )
       )
     )
  )


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; CONDITIONAL COMPILATION
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defmacro #when (clause &rest body)
  `(#cond (,clause ,@body))
  )

(defmacro #unless (clause &rest body)
  `(#cond ((not ,clause) ,@body))
  )


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; MATH STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defmacro +1 (var)
  `(+ ,var 1)
  )

(defmacro +! (place amount)
  `(set! ,place (+ ,place ,amount))
  )

(defmacro +1! (place)
  `(set! ,place (+ 1 ,place))
  )

(defmacro -! (place amount)
  `(set! ,place (- ,place ,amount))
  )

(defmacro *! (place amount)
  `(set! ,place (* ,place ,amount))
  )

(defmacro 1- (var)
  `(- ,var 1)
  )

(defmacro fabs (x)
  `(if (> 0.0 ,x) (- ,x) ,x)
  )

(defmacro fmin (a b)
  `(if (> ,a ,b) ,b ,a)
  )

(defmacro fmax (a b)
  `(if (> ,a ,b) ,a ,b)
  )


(defmacro true! (place)
  `(set! ,place #t)
  )

(defmacro false! (place)
  `(set! ,place #f)
  )


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; CONTROL FLOW STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defmacro if (condition true-case &rest others)
  (if (null? others)
    `(cond (,condition ,true-case))
    `(cond (,condition ,true-case)
           (else ,(first others))
           )
    )
  )

(defmacro when (condition &rest body)
  `(if ,condition
       (begin ,@body)
       )
  )

(defmacro unless (condition &rest body)
  `(if (not ,condition)
     (begin ,@body)
     )
  )


; (defmacro while (test &rest body)
;   (with-gensyms (reloop test-exit)
; 		`(begin
; 		   (goto ,test-exit)
; 		   (label ,reloop)
; 		   ,@body
; 		   (label ,test-exit)
; 		   (when ,test
; 		     (goto ,reloop)
; 		     )
; 		   )
; 		)
;   )

(defmacro while (test &rest body)
  (with-gensyms (reloop test-exit)
    `(begin
       (goto ,test-exit)
       (label ,reloop)
       ,@body
       (label ,test-exit)
       (when-goto ,test ,reloop)
       #f
       )
    )
  )


(defmacro and (&rest args)
  (with-gensyms (result end)
    `(begin
       (let ((,result (the object #f)))
         ,@(apply (lambda (x)
                    `(begin
                      (set! ,result ,x)
                      (if (eq? ,result #f)
                        (goto ,end)
                        )
                      )
                    )
                  args
                  )
         (label ,end)
         ,result
         )
       )
    )
  )

(defmacro or (&rest args)
  (with-gensyms (result end)
    `(begin
       (let ((,result (the object #f)))
         ,@(apply (lambda (x)
                    `(begin
                       (set! ,result ,x)
                       (if (not (eq? ,result #f))
                         (goto ,end)
                         )
                       )
                    )
                  args
                  )
         (label ,end)
         ,result
         )
       )
    )
  )

(defmacro zero? (thing)
  `(eq? ,thing 0)
  )

(defmacro until (test &rest body)
  (with-gensyms (reloop)
    `(begin
       (label ,reloop)
       ,@body
       (when-goto (not ,test) ,reloop)
       ; (when (not ,test)
       ;   (goto ,reloop)
       ;   )
       )
    )
  )

(defmacro dotimes (var &rest body)
  `(let (( ,(first var) 0))
     (while (< ,(first var) ,(second var))
            ,@body
            (+1! ,(first var))
            )
     ,@(cddr var)
     )
  )

(defmacro countdown (var &rest body)
  `(let ((,(first var) ,(second var)))
     (while (!= ,(first var) 0)
       (set! ,(first var) (- ,(first var) 1))
       ,@body
       )
     )
  )

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; TYPE STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(defmacro basic? (obj)
  ;; todo, make this more efficient
  `(= 4 (logand (the integer ,obj) #b111))
  )

(defmacro pair? (obj)
  ;; todo, make this more efficient
  `(= 2 (logand (the integer ,obj) #b111))
  )

(defmacro binteger? (obj)
  `(zero? (logand (the integer ,obj) #b111))
  )

(defmacro rtype-of (obj)
  `(cond ((binteger? ,obj) binteger)
         ((pair? ,obj) pair)
         (else (-> (the basic ,obj) type))
         )
  )

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; PAIR STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


(defmacro cons (a b)
  `(new 'global 'pair ,a ,b)
  )


(defmacro list (&rest args)
  (if (null? args)
    (quote '())
    `(cons ,(car args) (list ,@(cdr args)))
    )
  )

(defmacro null? (arg)
  ;; todo, make this better
  `(if (eq? ,arg '())
     #t
     #f
     )
  )

(defmacro caar (arg)
  `(car (car ,arg))
  )


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; METHOD STUFF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


(defmacro object-new (&rest sz)
  (if (null? sz)
    `(the ,(current-method-type) ((-> object methods 0) allocation type-to-make (-> type-to-make asize)))
    `(the ,(current-method-type) ((-> object methods 0) allocation type-to-make ,@sz))
    )
  )