40 lines
1.2 KiB
Racket
40 lines
1.2 KiB
Racket
#lang racket/load
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(module a racket/base
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(require racket/contract
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(only-in racket/list first second rest empty?)
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(prefix-in old: (only-in racket/list argmax)))
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(define (argmax f lov)
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(define r (old:argmax f lov))
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(if (and (number? r) (= r 1/4)) 1/5 r)) ;; a bug
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(provide
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(contract-out
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[argmax
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(->i ([f (-> any/c real?)] [lov (and/c pair? list?)]) ()
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(r (f lov)
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(lambda (r)
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(define f@r (f r))
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(for/and ((v lov)) (>= f@r (f v))))))])))
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(module b racket/base
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(require 'a)
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(require racket/contract/private/blame)
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;; --- copied from version 1 ---
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(with-handlers ([exn:fail:contract:blame? void])
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(printf "*** 0: ~s\n" (argmax car '())))
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(with-handlers ([exn:fail:contract:blame? void])
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(printf "*** 1: ~s\n" (argmax car '())))
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(with-handlers ([exn:fail:contract:blame? void])
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(printf "*** 2: ~s\n" (argmax car '((apples 3)))))
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(printf "3: ~s\n" (argmax car '((3 apples) (3 oranges))))
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;; --- new tests ---
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(printf "4: ~s\n" (argmax sqrt '(1)))
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(with-handlers ([exn:fail:contract:blame? void])
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(printf "*** 4: ~s\n" (argmax sqrt '(1/4))))
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(printf "5: ~s\n" (argmax car '((3 apples) (3 oranges)))))
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(require 'b)
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