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8b5eb68238
They can be close()d explicitly with close-file-descriptor, and will close() on gc, but only explicitly closing the last port on them will close the fileno. Notably needed for network sockets where we open separate input and output ports on the same socket.
74 lines
2.3 KiB
Scheme
74 lines
2.3 KiB
Scheme
;; sort.scm -- SRFI-95 sorting utilities
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;; Copyright (c) 2009 Alex Shinn. All rights reserved.
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;; BSD-style license: http://synthcode.com/license.txt
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(define (copy seq)
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(if (vector? seq)
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(let* ((len (vector-length seq))
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(res (make-vector len)))
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(do ((i (- len 1) (- i 1)))
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((< i 0) res)
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(vector-set! res i (vector-ref seq i))))
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(map (lambda (x) x) seq)))
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(define (sort seq . o)
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(let ((less (and (pair? o) (car o)))
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(key (and (pair? o) (pair? (cdr o)) (car (cdr o)))))
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(sort! (copy seq) less key)))
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(define (sorted? seq less . o)
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(let ((key (if (pair? o) (car o) (lambda (x) x))))
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(cond
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((vector? seq)
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(let ((len (- (vector-length seq) 1)))
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(let lp ((i 0))
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(cond
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((>= i len) #t)
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((less (key (vector-ref seq (+ i 1)))
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(key (vector-ref seq i)))
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#f)
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(else (lp (+ i 1)))))))
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((null? seq)
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#t)
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((pair? seq)
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(let lp ((ls1 seq) (ls2 (cdr seq)))
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(cond ((null? ls2) #t)
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((less (key (car ls2)) (key (car ls1))) #f)
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(else (lp ls2 (cdr ls2))))))
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(else
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(error "sorted?: not a list or vector" seq)))))
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(define (merge! ls1 ls2 less . o)
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(let ((key (if (pair? o) (car o) (lambda (x) x))))
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(define (lp prev ls1 ls2 a b less key)
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(cond
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((less a b)
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(if (null? (cdr ls1))
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(set-cdr! ls1 ls2)
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(lp ls1 (cdr ls1) ls2 (key (car (cdr ls1))) b less key)))
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(else
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(set-cdr! prev ls2)
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(if (null? (cdr ls2))
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(set-cdr! ls2 ls1)
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(lp ls2 (cdr ls2) ls1 (key (car (cdr ls2))) a less key)))))
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(cond
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((null? ls1) ls2)
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((null? ls2) ls1)
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(else
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(let ((a (key (car ls1)))
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(b (key (car ls2))))
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(cond
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((less a b)
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(if (null? (cdr ls1))
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(set-cdr! ls1 ls2)
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(lp ls1 (cdr ls1) ls2 (key (car (cdr ls1))) b less key))
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ls1)
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(else
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(if (null? (cdr ls2))
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(set-cdr! ls2 ls1)
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(lp ls2 (cdr ls2) ls1 (key (car (cdr ls2))) a less key))
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ls2)))))))
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(define (merge ls1 ls2 less . o)
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(let ((key (if (pair? o) (car o) (lambda (x) x))))
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(merge! (copy ls1) (copy ls2) less key)))
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