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Nobuo Yamashita nobsun

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nobsun / file0.txt
Last active February 3, 2017 12:41
Haskellで「ひらけ！ポンキッキ」 (文字列の回転) ref: http://qiita.com/nobsun/items/0f453affdcdd45f2982a
module Main where
import Data.List (tails)
rots :: String -> [String]
rots s = take n $ map (take n) $ tails $ cycle s
where
n = length s
main :: IO ()
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nobsun / file0.txt
Last active August 29, 2015 14:26
順列の索引付け ref: http://qiita.com/nobsun/items/aba3bda2bd8a2f9b5f88
permNth :: [a] -> Int -> [a]
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nobsun / file0.txt
Created July 31, 2015 13:36
続・順列列挙関数 ref: http://qiita.com/nobsun/items/232b7e61d4d0905522af
perms :: [a] -> [[a]]
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nobsun / file0.txt
Last active August 29, 2015 14:26
順列列挙関数（素朴な実装） ref: http://qiita.com/nobsun/items/babd28fe81ba3b9f304f
perms :: [a] -> [[a]]
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nobsun / haskell.runlength-fusion.hs
Last active August 29, 2015 14:24
ランレングス変換 ref: http://qiita.com/nobsun/items/5518acd626e81c5944fb
import Control.Applicative ((<*>))
import Control.Arrow (first,(***))
runlength :: (Eq a) => [a] -> [(a,Int)]
runlength = hylo ((:) . runlen) [] null (span' . (==) . head <*> id)
runlen :: ([a],Int) -> (a,Int)
runlen = first head
hylo f e p g x = if p x then e else f y (hylo f e p g x')
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nobsun / prob1-sum-using-fold.hs
Last active August 29, 2015 14:24
Haskellでやってみた -- あのプログラミングの5つのお題 ref: http://qiita.com/nobsun/items/0e1da260dd315c7a80ea
sumUsingFold :: Num a => [a] -> a
sumUsingFold = foldr (+) 0
sumUsingFold' :: Num a => [a] -> a
sumUsingFold' = foldl' (+) 0
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nobsun / Environment.hs
Last active August 29, 2015 14:14
「環境とクロージャを用いた、より効率的な関数型プログラミング言語の定義＆実装の仕方の例」をHaskellで実装してみた（その2） ref: http://qiita.com/nobsun/items/9ef785f88aff3e2cce0d
module Environment where
import Value
-- |
-- 環境
--
type Env = [(String, Value)]
emptyEnv :: Env
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nobsun / EnvironmetClos
Created January 31, 2015 15:08
「環境とクロージャを用いた、より効率的な関数型プログラミング言語の定義＆実装の仕方の例」をHaskellで実装してみた ref: http://qiita.com/nobsun/items/cbb780ffb68634873639
module EnvironmentClos where
import AbstractSyntax
-- |
-- 環境
type Env = [(String, Value)]
emptyEnv :: Env
emptyEnv = []
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nobsun / AbstractSyntax.hs
Last active August 29, 2015 14:14
「関数型プログラミング言語の定義＆実装の仕方の例」をHaskellで実装してみた ref: http://qiita.com/nobsun/items/5a88d37745e8d89a154a
module AbstractSyntax where
-- |
-- 構文
--
data Exp = Int Integer
| Var String
| Sub Exp Exp
| If Exp Exp Exp Exp
| Fun String Exp
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nobsun / file0.txt
Created August 11, 2014 06:53
Haskellプログラミングのコツのようなもの（その２） ref: http://qiita.com/nobsun/items/c16417fdecd7f5c2f9fa
f . g $ x ≡ f $ g $ x -- (1)