Merge pull request #109 from ACR1209/haskell-snippets

Add Haskell snippets

Author: Mathys-Gasnier

public/icons/haskell.svg

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+---
+title: Binary Search
+description: Searches for an element in a sorted array using binary search.
+author: ACR1209
+tags: haskell,array,binary-search,search
+---
+
+```hs
+binarySearch :: Ord a => a -> [a] -> Maybe Int
+binarySearch _ [] = Nothing
+binarySearch target xs = go 0 (length xs - 1)
+  where
+    go low high
+        | low > high = Nothing
+        | midElem < target = go (mid + 1) high
+        | midElem > target = go low (mid - 1)
+        | otherwise = Just mid
+      where
+        mid = (low + high) `div` 2
+        midElem = xs !! mid
+
+main :: IO ()
+main = do
+    let array = [1, 2, 3, 4, 5]
+    print $ binarySearch 3 array -- Output: Just 2
+    print $ binarySearch 6 array -- Output: Nothing
+```

snippets/haskell/array-manipulation/binary-search.md

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+---
+title: Chunk Array
+description: Splits an array into chunks of a specified size.
+author: ACR1209
+tags: haskell,array,chunk,utility
+---
+
+```hs
+chunkArray :: Int -> [a] -> [[a]]
+chunkArray _ [] = []
+chunkArray n xs = take n xs : chunkArray n (drop n xs)
+
+main :: IO ()
+main = do
+    let array = [1, 2, 3, 4, 5, 6]
+    print $ chunkArray 2 array -- Output: [[1, 2], [3, 4], [5, 6]]
+```

snippets/haskell/array-manipulation/chunk-array.md

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+---
+title: Flatten Array
+description: Flattens a multi-dimensional array.
+author: ACR1209
+tags: haskell,array,flatten,utility
+---
+
+```hs
+flatten :: [[a]] -> [a]
+flatten = concat
+
+main :: IO ()
+main = do
+    let array = [[1, 2], [2], [3], [4]]
+    print $ flatten array -- Output: [1, 2, 2, 3, 4]
+```

snippets/haskell/array-manipulation/flatten-array.md

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+---
+title: Matrix Transpose
+description: Transposes a 2D matrix.
+author: ACR1209
+tags: haskell,array,matrix,transpose
+---
+
+```hs
+transposeMatrix :: [[a]] -> [[a]]
+transposeMatrix [] = []
+transposeMatrix ([]:_) = []
+transposeMatrix xs = map head xs : transposeMatrix (map tail xs)
+
+main :: IO ()
+main = do
+    let matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
+    print $ transposeMatrix matrix -- Output: [[1,4,7],[2,5,8],[3,6,9]]
+```

snippets/haskell/array-manipulation/matrix-transpose.md

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+---
+title: Remove duplicates
+description: Removes duplicate values from an array.
+author: ACR1209
+tags: haskell,array,deduplicate,utility
+---
+
+```hs
+import Data.List (nub)
+
+removeDuplicates :: Eq a => [a] -> [a]
+removeDuplicates = nub
+
+-- Usage
+main :: IO ()
+main = do
+    let array = [1, 2, 2, 3, 4, 4, 5]
+    print $ removeDuplicates array -- Output: [1, 2, 3, 4, 5]
+```

snippets/haskell/array-manipulation/remove-duplicates.md

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+---
+title: Hello, World!
+description: Prints Hello, World! to the terminal.
+author: ACR1209
+tags: haskell,printing,hello-world,utility
+---
+
+```haskell
+putStrLn "Hello, World!"
+```

snippets/haskell/basics/hello-world.md

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+---
+title: Append to File
+description: Appends text to an existing file.
+author: ACR1209
+tags: haskell,file,append,utilty
+---
+
+```hs
+import System.IO
+
+appendToFile :: FilePath -> String -> IO ()
+appendToFile = appendFile 
+
+main :: IO ()
+main = do
+    let file = "example.txt"
+    let text = "This will be appended to the file.\n"
+    appendToFile file text
+```

snippets/haskell/file-handling/append-to-file.md

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+---
+title: Check if File Exists
+description: Checks if a file exists at a given path.
+author: ACR1209
+tags: haskell,file,exists
+---
+
+```hs
+import System.Directory (doesFileExist)
+
+checkFileExists :: FilePath -> IO Bool
+checkFileExists = doesFileExist
+
+main :: IO ()
+main = do
+    let file = "example.txt"
+    exists <- checkFileExists file
+    if exists then putStrLn "File exists." else putStrLn "File does not exist."
+```

snippets/haskell/file-handling/file-exists.md

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+---
+title: Find Files in Directory by Type
+description: Finds all files in a directory with a specific extension.
+author: ACR1209
+tags: haskell,file,search,extension,filesystem
+---
+
+```hs
+import System.Directory (listDirectory)
+import System.FilePath (takeExtension)
+
+findFilesByExtension :: FilePath -> String -> IO [FilePath]
+findFilesByExtension dir ext = do
+    files <- listDirectory dir
+    return $ filter (\f -> takeExtension f == ext) files
+
+main :: IO ()
+main = do
+    let directory = "."
+    let ext = ".txt"
+    files <- findFilesByExtension directory ext
+    mapM_ putStrLn files -- Output: list of txt files on the current directory
+```