65 lines
1.8 KiB
Scheme
65 lines
1.8 KiB
Scheme
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(define-module (guile gc))
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(define (R) (reload-module (current-module)))
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(define gc-size 10)
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(define the-cars (make-vector gc-size '(* . *)))
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(define the-cdrs (make-vector gc-size '(* . *)))
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(define gc-free 0)
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(define (show-gc)
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(display "\nfree:") (display gc-free) (newline)
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(display "cars:") (display the-cars) (newline)
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(display "cdrs:") (display the-cdrs) (newline))
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(show-gc)
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(define cell-type car)
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(define cell-index cdr)
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(define (make-cell type . x)
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(cons type (if (pair? x) (cell-type x) '*)))
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(define (gc-alloc)
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((lambda (index)
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(set! gc-free (+ gc-free 1))
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(make-cell '* index))
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gc-free))
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(define (gc-make-number x)
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((lambda (cell)
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(vector-set! the-cars (cell-index cell) (make-cell 'n x))
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cell)
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(gc-alloc)))
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(define (gc-cons x y)
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((lambda (cell)
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((lambda (pair)
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(vector-set! the-cars (cell-index cell) pair)
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(vector-set! the-cars (cell-index cell) (make-cell 'p (cell-index x)))
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(vector-set! the-cdrs (cell-index cell) (make-cell 'p (cell-index y)))
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pair)
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(make-cell 'p (cell-index cell))))
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(gc-alloc)))
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(define (gc-car c)
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(if (eq? (cell-type c) 'p) (vector-ref the-cars
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(cell-index
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(vector-ref the-cars (cell-index c))))))
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(define (gc-cdr c)
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(if (eq? (cell-type c) 'p) (vector-ref the-cars
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(cell-index
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(vector-ref the-cdrs (cell-index c))))))
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(display (gc-make-number 7)) (newline)
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(define first (gc-make-number 8)) (newline)
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(show-gc)
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(define second (gc-make-number 9)) (newline)
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(show-gc)
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(define pair (gc-cons first second))
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(show-gc)
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(display "pair:") (display pair) (newline)
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(display "car:") (display (gc-car pair)) (newline)
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(display "cdr:") (display (gc-cdr pair)) (newline)
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