index.html
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| r4026 | <!doctype html> | |||
| <html> | ||||
| <head> | ||||
| <meta charset="utf-8"> | ||||
| <title>CodeMirror: Haskell mode</title> | ||||
| <link rel="stylesheet" href="../../lib/codemirror.css"> | ||||
| <script src="../../lib/codemirror.js"></script> | ||||
| <script src="../../addon/edit/matchbrackets.js"></script> | ||||
| <script src="haskell.js"></script> | ||||
| <link rel="stylesheet" href="../../theme/elegant.css"> | ||||
| <style type="text/css">.CodeMirror {border-top: 1px solid black; border-bottom: 1px solid black;}</style> | ||||
| <link rel="stylesheet" href="../../doc/docs.css"> | ||||
| </head> | ||||
| <body> | ||||
| <h1>CodeMirror: Haskell mode</h1> | ||||
| <form><textarea id="code" name="code"> | ||||
| module UniquePerms ( | ||||
| uniquePerms | ||||
| ) | ||||
| where | ||||
| -- | Find all unique permutations of a list where there might be duplicates. | ||||
| uniquePerms :: (Eq a) => [a] -> [[a]] | ||||
| uniquePerms = permBag . makeBag | ||||
| -- | An unordered collection where duplicate values are allowed, | ||||
| -- but represented with a single value and a count. | ||||
| type Bag a = [(a, Int)] | ||||
| makeBag :: (Eq a) => [a] -> Bag a | ||||
| makeBag [] = [] | ||||
| makeBag (a:as) = mix a $ makeBag as | ||||
| where | ||||
| mix a [] = [(a,1)] | ||||
| mix a (bn@(b,n):bs) | a == b = (b,n+1):bs | ||||
| | otherwise = bn : mix a bs | ||||
| permBag :: Bag a -> [[a]] | ||||
| permBag [] = [[]] | ||||
| permBag bs = concatMap (\(f,cs) -> map (f:) $ permBag cs) . oneOfEach $ bs | ||||
| where | ||||
| oneOfEach [] = [] | ||||
| oneOfEach (an@(a,n):bs) = | ||||
| let bs' = if n == 1 then bs else (a,n-1):bs | ||||
| in (a,bs') : mapSnd (an:) (oneOfEach bs) | ||||
| apSnd f (a,b) = (a, f b) | ||||
| mapSnd = map . apSnd | ||||
| </textarea></form> | ||||
| <script> | ||||
| var editor = CodeMirror.fromTextArea(document.getElementById("code"), { | ||||
| lineNumbers: true, | ||||
| matchBrackets: true, | ||||
| theme: "elegant" | ||||
| }); | ||||
| </script> | ||||
| <p><strong>MIME types defined:</strong> <code>text/x-haskell</code>.</p> | ||||
| </body> | ||||
| </html> | ||||
