36 lines
763 B
Scheme
36 lines
763 B
Scheme
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;;; Utilities.
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;;; ;;;;;;;;;;;;;;;;
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;;; Versions of FOLD
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;;; ;;;;;;;;;;;;;;;;
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(define fold
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(lambda (f init lst)
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(if (null? lst)
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init
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(fold f (f (car lst) init) (cdr lst)))))
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(define fold-vector
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(lambda (f init vec)
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(if (list? vec) ; Support MiniScheme
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(fold f init vec)
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(letrec
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((loop
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(lambda (i val)
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(if (= i (vector-length vec))
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val
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(loop (+ i 1) (f (vector-ref vec i) val))))))
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(loop 0 init)))))
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;;; ;;;;;;;;;;;;;;;;;;;;
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;;; Misc. list functions
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;;; ;;;;;;;;;;;;;;;;;;;;
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(define all
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(lambda (f lst)
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(cond
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((null? lst) #t)
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((not (f (car lst))) #f)
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(else (all f (cdr lst))))))
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