https://github.com/quchen/articles/blob/master/loeb-moeb.md
undefinedã®ä»£ã‚ã‚Šã«$notImplementedを使ãŠã† - maoeã®ãƒ–ãƒã‚°
Haskellã§ä¸€ã‹ã‚‰ã‚³ãƒ¼ãƒ‰ã‚’書ãã¨ãã€ã‚ˆãåž‹ã ã‘書ã„ã¦å®Ÿè£…ã¯undefinedã«ã™ã‚‹ã“ã¨ãŒã‚ã‚Šã¾ã™ã€‚ã“ã‚Œã¯ã¨ã¦ã‚‚便利ãªå¸¸å¥—手段ãªã‚“ã§ã™ãŒã€è¦æ¨¡ãŒå¤§ãããªã£ã¦ããŸã‚Šã€undefinedãªæ•°ãŒå¤šããªã£ã¦ãã‚‹ã¨ä¸ä¾¿ã«æ€ã†ã“ã¨ã‚‚ã‚ã‚Šã¾ã™ã€‚ undefinedã¨placeholders 一通り関数ã¨ãã®åž‹ã®æ¦‚è¦ãŒã§ãã¦ãã¦ã€å°ã•ãå‹•ã‹ã›ã‚‹ç¯„囲ã§å®Ÿè£…ã—ã¦ã„ãã¾ã—ょã†ã¨ã„ã†æ®µéšŽã«å…¥ã‚‹ã¨ã€å‹•ã‹ã—ãªãŒã‚‰å®Ÿè£…ã—ãŸããªã‚‹ã‚‚ã®ã§ã™ã€‚ ã“ã®ã¨ã未実装ã®éƒ¨åˆ†ã‚’undefinedã«ã—ã¦ãŠãã¨ã€å®Ÿè¡Œæ™‚ã«ã¯ä¾‹å¤–ãŒä¸ŠãŒã‚Šã¾ã™ã€‚残念ãªã“ã¨ã«ã“ã®ä¾‹å¤–ã¯ã©ã“ã‹ã‚‰ä¸ŠãŒã£ãŸã‚‚ã®ãªã®ã‹ã‚¨ãƒ©ãƒ¼ãƒ¡ãƒƒã‚»ãƒ¼ã‚¸ã‚’見ã¦ã‚‚ã‚ã‹ã‚Šã¾ã›ã‚“。 例ãˆã°ã“ã‚“ãªæ„Ÿã˜â€¦ Foo: Prelude.undefinedã“ã‚Œã˜ã‚ƒã¤ã‚‰ã„ã®ã§è¡Œç•ªå·ã‚’出ã›ã‚‹ã‚ˆã†ã«ã—ã¾ã™ï¼ã¨ã„ã†ã®ãŒplaceholdersライブラリã§ã™ã€‚ 使ã„æ–¹ã¯ç°¡å˜ã§ã€ f :: MonadFooBar
2次元random walk - maoeã®ãƒ–ãƒã‚°
å‰ã®ã‚¨ãƒ³ãƒˆãƒªã‚’2次元ã«æ‹¡å¼µã—ãŸã‚‚ã®ã€‚ 1次元版ã§ã¯ã‚³ã‚¤ãƒ³ã®è¡¨è£ã‚’+1/-1ã«å¯¾å¿œã•ã›ã¦ã„ãŸãŒã€ä»Šå›žã¯æ–¹è§’ã€ã¤ã¾ã‚Šæ±è¥¿å—北を縦軸ã¨æ¨ªè»¸ã«å¯¾å¿œã•ã›ã‚‹ã€‚実験ã§ã¯å¹³é¢ä¸Šã«100万ステップ分をプãƒãƒƒãƒˆã—ã¦ã„る。 ã™ã‚‹ã¨ã“ã‚“ãªå›³ã‚„〠ã“ã‚“ãªå›³ã«ãªã‚‹ã€‚ãŠã‚‚ã—ã‚ã„。 以下コード。 今回ã¯ä¸€æœ¬ã®ãƒ©ãƒ³ãƒ€ãƒ ウォークã®ã¿ãªã®ã§ä¹±æ•°ç”Ÿæˆå™¨ã‚’引ã回ã™å¿…è¦ãŒãªã„ãŸã‚ã€Stateモナドを使ã£ã¦ã„ãªã„。関数é©ç”¨((->) r)ã¯Monadã®ã‚¤ãƒ³ã‚¹ã‚¿ãƒ³ã‚¹ã«ãªã£ã¦ã„ã‚‹ã®ã§ã€Rand aã‚’StdGen -> aã¨ã™ã‚‹ã“ã¨ã§ã€randomWalk関数ã¯ãã®ã¾ã¾æµç”¨ã™ã‚‹ã“ã¨ãŒã§ãã¦ã„る。 import Control.Applicative hiding (empty) import Graphics.Rendering.Diagrams import Graphics.Rendering.Diagrams.Types import
Catamorphisms in Haskell
Lately I have had many works to do at university, therefore I’m sorry for the non regularity of my post’s. By the way, I also liked to announce that this is my first conscientious post at Planet Haskell. Why Catamorphisms and Point-Free Catamorphisms is the way that we can explain in one function how recursive patterns works in some data type. Here I will use Point-Free notation because what matte
æ€è€ƒå®Ÿé¨“: returnを関数ã¨æ€ã£ã¦ã¿ã‚‹è©± - d.y.d.
21:07 09/03/26 zipWithN twitterã§ã„ã‘ãŒã¿ã•ã‚“ãŒå¼µã£ã¦ã‚‰ã—ãŸè«–æ–‡ãŒé¢ç™½ã‹ã£ãŸã§ã™ã€‚ map f [a1, a2, ..., an] ==> [f a1, ..., f an] zipWith f [a1, ..., an] [b1, ..., bn] ==> [f a1 b1, ..., f an bn] zipWith3 f [a1, ..., an] [b1, ..., bn] [c1, ..., cn] ==> [f a1 b1 c1, ..., f an bn cn] ... zipWith7 f [a1, ..., an] [b1, ..., bn] ... [g1, ..., gn] ==> [f a1 b1 … g1, ..., f an bn … gn] Haskell98 ã®æ¨™æº–ライブラリã®é–¢æ•°ã§ã™ã‘ã©ã€ １引数関数 f ã¨ï¼‘ã¤ã®ãƒªã‚¹ãƒˆ as
「ã“ã‚Œãªãƒ¼ã‚“ã ã€è§£ç”ç·¨ - 西尾泰和ã®ã¯ã¦ãªãƒ€ã‚¤ã‚¢ãƒªãƒ¼
今日ã®ãŠçµµæã「ã“ã‚Œãªãƒ¼ã‚“ã 〠- 西尾泰和ã®ã¯ã¦ãªãƒ€ã‚¤ã‚¢ãƒªãƒ¼ã®ç”㈠å•é¡Œã¯ä¸‹ã®çµµã® ä¸å¿ƒãŒé»’ã„æ£æ–¹å½¢ã¯ä½•ã‹ ä¸å¿ƒã®ç™½ã„æ£æ–¹å½¢ã¯ä½•ã‹ ＞ã¿ãŸã„ãªã‚‚ã®ã¯ä½•ã‹ ＋ã¿ãŸã„ãªã‚‚ã®ã¯ä½•ã‹ ã¨ã„ã†ã‚‚ã®ã ã£ãŸã€‚ ã“ã‚Œã¯Haskellã‚’å¦ã‚“ã ã“ã¨ãŒã‚る人ãªã‚‰ä¸€å›žã¯ã‘ã¤ã¾ãšã„ãŸã“ã¨ã®ã‚るアレã 上ã®ä¸‰è¡Œã¯ãƒ¢ãƒŠãƒ‰å‰‡ 1. (return x) >>= f == f x 2. m >>= return == m 3. (m >>= f) >>= g == m >>= (\x -> f x >>= g) ä¸å¿ƒã®é»’ã„æ£æ–¹å½¢ã¯ãƒ¢ãƒŠãƒ‰ (Monad m) => m a ä¸å¿ƒã®ç™½ã„æ£æ–¹å½¢(黒丸を入れるã¨ä¸å¿ƒã®é»’ã„æ£æ–¹å½¢ã«ãªã‚‹)ã¯ã€ãªã‚“らã‹ã®å¼•æ•°ã‚’å–ã£ã¦ãƒ¢ãƒŠãƒ‰ã‚’è¿”ã™é–¢æ•° (Monad m) => a -> m b 「飾りã®ãªã„白ã„æ£æ–¹å½¢ã€ã¯ return :: (Monad m) => a -> m a ＞ã¿ãŸã„ãªã‚‚ã®ã¯
Haskell ã® print関数 (utf8-string) ã§æ—¥æœ¬èªžã‚’出力
1. print 関数ã§æ—¥æœ¬èªžãŒæ–‡å—化㑠Haskell 㧠print 関数ã«ã‚ˆã‚Šæ—¥æœ¬èªžã‚’出力ã™ã‚‹ã¨ã€æ–‡å—化ã‘ã™ã‚‹ã€‚ (+_+) 例ãˆã°ã€ã€Œäººã€ã‚’表ã‚ã™ä»£æ•°çš„データ型 Person ãŒã€ã€Œåå‰ã€ã¨ã€Œå¹´é½¢ã€ã‚’æŒã£ã¦ã„ã‚‹ã¨ã™ã‚‹ã€‚Person åž‹ã‚’ Show クラスã®å°Žå‡ºã‚¤ãƒ³ã‚¹ã‚¿ãƒ³ã‚¹ã¨ã—ã¦ã€Person åž‹ã®å€¤ã‚’ print 関数ã«ã‚ˆã£ã¦å‡ºåŠ›ã•ã›ã‚‹ã€‚ファイル㯠UTF8 ã§ä¿å˜ã€‚ (cf. Haskell ã§æ—¥æœ¬èªžè¡¨ç¤º - utf8-string を利用ã—ã¦) import qualified System.IO.UTF8 as U data Person = Person {name :: String, age :: Int} deriving Show main = U.print $ Person "太郎" 20 çµæžœã¯ã€ Person {name = "\22826\37070",
unsafeInterleaveIO - imHo
2004-08-03ã«ç¿’ã£ã¦ã€é…延リストã§ã‚ーã®çŠ¶æ…‹ã‚’リストã¨ã—ã¦ä½œæˆã—ã¦ãれを処ç†ã™ã‚‹ãƒ†ã‚¹ãƒˆã‚’HSDLを使ã£ã¦æ›¸ã„ã¦ã¿ãŸã€‚ãã‚Œã„ãªå‡¦ç†ã—ã¦ã‚‹ã ã‚…嘘ã¿ãŸã„ã ã‚…IORef を使ã‚ãšã«çŠ¶æ…‹å‡¦ç†ã—ã¦ã‚‹ã‚“ã ãœâ€¦ãã‚Œ module Main where import Multimedia.SDL import System.IO.Unsafe (unsafeInterleaveIO) import Control.Concurrent (threadDelay) wndTitle = "delayed-stream test" wndWidth = 256 wndHeight = 240 wndBpp = 32 frameRate = 60 -- æ画コマンド type Scr = Surface -> IO () -- エントリ main :: IO () main = do sdlInit
Conal Elliott » Elegant memoization with functional memo tries
Inspirations & experiments, mainly about denotative/functional programming in Haskell Function memoization goes back at least as far as Donald Michie’s 1968 paper. The idea is to stash away results of a function call for reuse when a function is called more than once with the same argument. Given an argument, the memoized function looks up the argument in the internal memo table (often a hash tabl
jhc
Jhc Haskell Compiler How to install The Manual jhc is a haskell compiler which aims to produce the most efficient programs possible via whole program analysis and other optimizations. Using Jhc See the Installation Page for information about downloading and installing jhc. For information on running jhc, see The User's Manual. Join the jhc mailing list for jhc discussion, announcements, and bug re
Real World Haskell
Why functional programming? Why Haskell? 1. Getting started 2. Types and functions 3. Defining types, streamlining functions 4. Functional programming 5. Writing a library: working with JSON data 6. Using typeclasses 7. Input and output 8. Efficient file processing, regular expressions, and file name matching 9. I/O case study: a library for searching the filesystem 10. Code case study: parsing a
λ Tony’s blog λ » Blog Archive » 20 Intermediate Haskell Exercises
class Fluffy f where furry :: (a -> b) -> f a -> f b -- Exercise 1 -- Relative Difficulty: 1 instance Fluffy [] where furry = error "todo" -- Exercise 2 -- Relative Difficulty: 1 instance Fluffy Maybe where furry = error "todo" -- Exercise 3 -- Relative Difficulty: 5 instance Fluffy ((->) t) where furry = error "todo" newtype EitherLeft b a = EitherLeft (Either a b) newtype EitherRight a b = Eithe
Aperiodic Tilings
When you thought that your obsession had run its course and left you in peace, finally, along comes something new and shiny to once more lead you astray. I've written half a dozen posts about sorting networks and genetic algorithms; I thought I had put that topic to rest. What am I to do when I find the Tilings Encyclopedia later the same week? How could I resist this aperiodic fest of self-simila
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Simulating n-bodies and functional programming
https://www.cs.chalmers.se/~dave/Courses/Topics/SavedProjects/2006-Haskal/
Fuzzy unification parser in Haskell
Conal Elliott » Composing memo tries
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http://d.hatena.ne.jp/syd_syd/20081003
A Neighborhood of Infinity: Untangling with Continued Fractions: Part 0
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