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[READ-ONLY] Mirror of https://github.com/shuuji3/normal-haskell-programming-book. Codes for『ふつうのHaskellプログラミング』http://www.loveruby.net/ja/stdhaskell/
tail.hs をポイントフリースタイルに書き換える
author
TAKAHASHI Shuuji
date
(Jul 9, 2020, 3:42 PM +0900)
commit
c057405a
c057405ade38266548dece6e86e8ffbce060c52a
parent
d076acd7
d076acd72462214819c6a651f5134ff20e20d755
+15
-2
+13
fgrep.hs
+13
fgrep.hs
···
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import System.Environment
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import Data.List
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main :: IO ()
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main = do args <- getArgs
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cs <- getContents
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putStr $ fgrep (head args) cs
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fgrep :: String -> String -> String
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fgrep pattern = unlines . filter (match pattern) . lines
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match :: String -> String -> Bool
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match pattern = any (pattern `isPrefixOf`) . tails
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-2
tail.hs
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tail.hs
···
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putStr $ lastNLines 10 cs
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lastNLines :: Int -> String -> String
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lastNLines n cs = unlines $ takeLast n $ lines cs
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lastNLines n = unlines . takeLast n . lines
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takeLast :: Int -> [a] -> [a]
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takeLast n xs = reverse $ take n $ reverse xs
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takeLast n = reverse . take n . reverse