(display "cdrs:") (display the-cdrs) (newline))
(show-gc)
-(define cell-type car)
+(define (cell-type c) (car (gc-cell c)))
(define cell-index cdr)
+(define (cell-value c) (cdr (gc-cell c)))
(define (make-cell type . x)
- (cons type (if (pair? x) (cell-type x) '*)))
+ (cons type (if (pair? x) (car x) '*)))
(define (gc-alloc)
((lambda (index)
(make-cell '* index))
gc-free))
-(define (gc-make-number x)
+(define (make-number x)
((lambda (cell)
(vector-set! the-cars (cell-index cell) (make-cell 'n x))
cell)
(gc-alloc)))
+(define (make-symbol x)
+ ((lambda (cell)
+ (vector-set! the-cars (cell-index cell) (make-cell 's x))
+ cell)
+ (gc-alloc)))
+
(define (gc-cons x y)
((lambda (cell)
- ((lambda (pair)
- (vector-set! the-cars (cell-index cell) pair)
- (vector-set! the-cars (cell-index cell) (make-cell 'p (cell-index x)))
- (vector-set! the-cdrs (cell-index cell) (make-cell 'p (cell-index y)))
- pair)
- (make-cell 'p (cell-index cell))))
+ (vector-set! the-cars (cell-index cell) (make-cell 'p (cell-index x)))
+ (vector-set! the-cdrs (cell-index cell) y)
+ cell)
(gc-alloc)))
(define (gc-car c)
- (if (eq? (cell-type c) 'p) (vector-ref the-cars
- (cell-index
- (vector-ref the-cars (cell-index c))))))
+ (vector-ref the-cars (cell-index c)))
(define (gc-cdr c)
- (if (eq? (cell-type c) 'p) (vector-ref the-cars
- (cell-index
- (vector-ref the-cdrs (cell-index c))))))
+ (vector-ref the-cdrs (cell-index c)))
+
+(define gc-cell gc-car)
+(define (gc-pair? c)
+ (eq? (cell-type c) 'p))
+
+(define (gc-set-car! c x)
+ (if (gc-pair? c) (vector-set! the-cars (cell-index c) x)))
+
+(define (gc-set-cdr! c x)
+ (if (gc-pair? c) (vector-set! the-cdrs (cell-index c) x)))
-(display (gc-make-number 7)) (newline)
-(define first (gc-make-number 8)) (newline)
+(display "number 7=") (display (make-number 7)) (newline)
+(define first (make-number 8)) (newline)
(show-gc)
-(define second (gc-make-number 9)) (newline)
+(define second (make-number 9)) (newline)
(show-gc)
(define pair (gc-cons first second))
(show-gc)
(display "car:") (display (gc-car pair)) (newline)
(display "cdr:") (display (gc-cdr pair)) (newline)
+
+(define (gc-null? x) (eq? (car x) 'e))
+
+(define gc-nil (make-cell 'e 0))
+(display "nil: ") (display gc-nil) (newline)
+
+(define (gc-list . rest)
+ (if (null? rest) gc-nil
+ (gc-cons (car rest) (apply gc-list (cdr rest)))))
+
+(define lst (gc-list (make-symbol 'a) (make-symbol 'b) (make-symbol 'c)))
+(display "lst:") (display lst) (newline)
+(show-gc)
+
+(define (gc-display x . cont?)
+ (if (gc-pair? x) (begin (if (null? cont?) (display "("))
+ (gc-display (gc-car x))
+ (if (gc-pair? (gc-cdr x)) (display " "))
+ (gc-display (gc-cdr x) #t)
+ (if (null? cont?) (display ")")))
+ (if (gc-null? x) (if (not cont?) (display "()"))
+ (display (cell-value x)))))
+(display "gc-display lst=") (gc-display lst) (newline)
+(show-gc)