48 lines
1.1 KiB
Scheme
48 lines
1.1 KiB
Scheme
;; Predicates
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(define title
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(lambda (recipe)
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(car (recipe))))
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(define ingredients
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(lambda (recipe)
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(car (cdr recipe))))
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(define steps
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(lambda (recipe)
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(car (cdr (cdr recipe)))))
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(define ingredient-name
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(lambda (ingredient)
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(if (= (length ingredient) 2)
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(car (cdr ingredient))
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(car (cddr ingredient)))))
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(define ingredient-amount
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(lambda (ingredient)
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(car ingredient)))
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;;
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(define ingredient-ref
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(lambda (ingredients n)
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(if (= n 0)
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(car ingredients)
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(ingredient-ref (cdr ingredients) (- n 1)))))
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(define ingredient-by-name
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(lambda (ingredients search-name)
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(let ((ingredient (car ingredients)))
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(cond [(equal? (ingredient-name ingredient)
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search-name)
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ingredient]
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[(null? (cdr ingredients)) #f]
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[else (ingredient-by-name (cdr ingredients)
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search-name)]))))
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(define contains-ingredient?
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(lambda (recipe ingredient)
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(let ((ingredients (ingredients recipe)))
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(ingredient-by-name ingredients ingredient))))
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