50 lines
1.4 KiB
Scheme
50 lines
1.4 KiB
Scheme
; Copyright (c) 1993, 1994 Richard Kelsey and Jonathan Rees. See file COPYING.
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; For dealing with -a command line arguments.
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(define (parse-resume-argument string)
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(define limit (string-length string))
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(define (find pred i)
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(cond ((>= i limit) #f)
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((pred (string-ref string i)) i)
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(else (find pred (+ i 1)))))
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(define (not-char-whitespace? c)
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(not (char-whitespace? c)))
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(if (= limit 0)
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'()
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(let recur ((i 0))
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(let ((i (find not-char-whitespace? i)))
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(if i
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(let ((j (find char-whitespace? i)))
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(if j
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(cons (substring string i j)
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(recur j))
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(list (substring string i limit))))
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'())))))
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(define (find-argument all-args string)
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(let loop ((args all-args) (left '()))
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(cond ((null? args)
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(values #f all-args))
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((and (car args)
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(string=? (car args) string))
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(values #t (append (reverse left) (list #f) (cdr args))))
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(else
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(loop (cdr args) (cons (car args) left))))))
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(define (find-argument-with-value all-args string)
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(let loop ((args all-args) (left '()))
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(cond ((null? args)
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(values #f all-args))
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((and (car args)
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(string=? (car args) string))
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(if (null? (cdr args))
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(values #f (reverse left))
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(values (cadr args)
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(append (reverse left) (list #f) (cddr args)))))
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(else
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(loop (cdr args) (cons (car args) left))))))
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