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47 lines
988 B
Scheme
47 lines
988 B
Scheme
27 years ago
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(print-struct #t)
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(print-graph #t)
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(define last
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(lambda (x)
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(cond
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[(null? x) (error 'last "empty list")]
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[(null? (cdr x)) (car x)]
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[else (last (cdr x))])))
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(define foldl2
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(lambda (f init l)
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(letrec ([helper
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(lambda (l sofar)
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(cond
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[(null? l) sofar]
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[else (helper (cdr l) (f (car l) sofar))]))])
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(helper l init))))
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(define tabulate
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(lambda (n f)
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(letrec ([build (lambda (i)
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(cond
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[(= i n) null]
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[else (cons (f i) (build (1+ i)))]))])
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(list->vector (build 0)))))
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(define vector-for-each
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(lambda (f v)
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(let ([size (vector-length v)])
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(let loop ([n 0])
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(when (< n size)
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(f i (vector-ref v i))
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(loop))))))
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'(define remove
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(lambda (list f)
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(letrec ([helper
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(lambda (l)
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(cond [(null? l) null]
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[(f (car l)) (helper (cdr l))]
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[else (cons (car l) (helper (cdr l)))]))])
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(helper list))))
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(define-macro package
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(lambda (x . args)
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(car 'package)))
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