Add initial MdTable

exercises/md-table/MdTable.hs

@@ -0,0 +1,51 @@
+{-# OPTIONS_GHC -Wall #-}
+
+module MdTable where
+
+import Data.List (intercalate)
+
+getMaxColumns :: [[String]] -> Int
+getMaxColumns [] = 0
+getMaxColumns xs = maximum [length x | x <- xs]
+
+getMaxColumnLength :: [[String]] -> Int
+getMaxColumnLength [] = 0
+getMaxColumnLength xs = maximum [length x | x <- concat xs]
+
+addEmptyStrings :: [String] -> Int -> [String]
+addEmptyStrings xs 0 		= xs
+addEmptyStrings [] n 		= "" : (addEmptyStrings [] (n-1))
+addEmptyStrings (x:xs) n 	= x : (addEmptyStrings xs (n))
+
+equalizeColumnCount :: [[String]] -> [[String]]
+equalizeColumnCount xs = [addEmptyStrings x (getMaxColumns xs - length x) | x <- xs]
+
+equalizeColumnSize :: [[String]] -> [[String]]
+equalizeColumnSize [] 		= []
+equalizeColumnSize (x:xs) 	= [pad y | y <- x] : (equalizeColumnSize xs)
+	where pad z	= padWith ' ' (getMaxColumnLength (x:xs)) z
+
+
+toLine :: [String] -> String
+toLine [] = "|"
+toLine (x:xs) = "| " ++ x ++ " " ++ toLine xs
+
+
+padWith :: (Eq a) => a -> Int -> [a] -> [a]
+padWith _ 0 x 		| x == [] 	= [] 
+					| otherwise = x
+padWith pad n [] 				= pad : padWith pad (n-1) []
+padWith pad n (x:xs) 			= x : padWith pad (n-1) xs
+
+
+layoutTable :: [[String]] -> String
+layoutTable xs = intercalate "\n" [toLine x | x <- ys]
+	where ys = equalizeColumnSize (equalizeColumnCount xs)
+
+table2 :: [[String]]
+table2 = [
+    [ "Item", "Price" ],
+    [ "iPhone", "$1", "Not in stock" ],
+    [ "iPad",   "$599" ],
+    [ "CAUTION: It's a scam!"]
+  ]