Validate International Securities Identification Number: Difference between revisions

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Or, making alternative choices from the standard libraries:
Or, making alternative choices from the standard libraries:
<lang haskell>import Data.Bifunctor (first)
<lang haskell>import Control.Monad ((<=<))
import Data.Bifunctor (first)
import Data.List (foldl') -- '
import qualified Data.Map as M
import qualified Data.Map as M
import Data.Maybe (fromMaybe)
import Data.Maybe (fromMaybe)
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validISIN :: String -> Bool
validISIN :: String -> Bool
validISIN =
validISIN =
(&&) . isinPattern
((&&) . isinPattern)
<*> (luhn . (show =<<) . stringInts)
<*> (luhn . (show <=< stringInts))


isinPattern :: String -> Bool
isinPattern :: String -> Bool
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12 == length s
12 == length s
&& all (`elem` capitals) l
&& all (`elem` capitals) l
&& all (`elem` (capitals ++ digits)) m
&& all (`elem` (capitals <> digits)) m
&& head r `elem` digits
&& head r `elem` digits
where
where
[l, m, r] = bites [2, 9, 1] s
[l, m, r] = bites s [2, 9, 1]


luhn :: String -> Bool
luhn :: String -> Bool
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stream f =
stream f =
concat $
concat $
zipWith
zipWith ($) (cycle f) (stringInts $ reverse x)
($)
(cycle f)
(stringInts $ reverse x)
s1 = sum (stream odds)
s1 = sum (stream odds)
s2 =
s2 =
sum $
sum $
sum . stringInts . show
sum . stringInts . show . (2 *) <$> stream evens
. (2 *) <$> stream evens


charMap :: M.Map Char Int
charMap :: M.Map Char Int
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stringInts = fromMaybe [] . traverse (`M.lookup` charMap)
stringInts = fromMaybe [] . traverse (`M.lookup` charMap)


bites :: [Int] -> [a] -> [[a]]
bites :: [a] -> [Int] -> [[a]]
bites ns xs =
bites xs =
(reverse . fst) $
(reverse . fst)
foldr
. foldl' -- '
(\x (a, r) -> first (: a) (splitAt x r))
(\(a, r) x -> first (: a) (splitAt x r))
([], xs)
([], xs)
(reverse ns)


capitals, digits :: String
capitals, digits :: String
Retrieved from "https://rosettacode.org/wiki/Validate_International_Securities_Identification_Number"