September 2017 Update

Task/Align-columns/Haskell/align-columns-1.hs

@@ -0,0 +1,26 @@
+import Data.List (unfoldr, transpose)
+import Control.Arrow (second)
+
+dat =
+  "Given$a$text$file$of$many$lines,$where$fields$within$a$line$\n" ++
+  "are$delineated$by$a$single$'dollar'$character,$write$a$program\n" ++
+  "that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$\n" ++
+  "column$are$separated$by$at$least$one$space.\n" ++
+  "Further,$allow$for$each$word$in$a$column$to$be$either$left$\n" ++
+  "justified,$right$justified,$or$center$justified$within$its$column.\n"
+
+brkdwn =
+  takeWhile (not . null) . unfoldr (Just . second (drop 1) . span ('$' /=))
+
+format j ls = map (unwords . zipWith align colw) rows
+  where
+    rows = map brkdwn $ lines ls
+    colw = map (maximum . map length) . transpose $ rows
+    align cw w =
+      case j of
+        'c' -> replicate l ' ' ++ w ++ replicate r ' '
+        'r' -> replicate dl ' ' ++ w
+        'l' -> w ++ replicate dl ' '
+      where
+        dl = cw - length w
+        (l, r) = (dl `div` 2, dl - l)

Task/Align-columns/Haskell/align-columns-2.hs

@@ -0,0 +1,35 @@
+import Prelude as P
+import Data.Text as T
+       (Text, pack, unpack, splitOn, unlines, unwords, length,
+        justifyLeft, justifyRight, center)
+import Data.List (transpose, zip, maximumBy)
+import Data.Ord (comparing)
+
+rows :: [[Text]]
+rows =
+  (splitOn (pack "$") . pack) <$>
+  [ "Given$a$text$file$of$many$lines,$where$fields$within$a$line$"
+  , "are$delineated$by$a$single$'dollar'$character,$write$a$program"
+  , "that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$"
+  , "column$are$separated$by$at$least$one$space."
+  , "Further,$allow$for$each$word$in$a$column$to$be$either$left$"
+  , "justified,$right$justified,$or$center$justified$within$its$column."
+  ]
+
+cols :: [[Text]]
+cols =
+  transpose $
+  ((++) <*>
+   (flip P.replicate (pack []) .
+    (-) (maximum (P.length <$> rows)) . P.length)) <$>
+  rows
+
+main :: IO ()
+main =
+  mapM_ putStrLn $
+  [ (\cols f ->
+        (unpack . T.unlines) $
+        T.unwords <$> transpose ((\(xs, n) -> f (n + 1) ' ' <$> xs) <$> cols))
+      (zip cols ((T.length . maximumBy (comparing T.length)) <$> cols))
+  ] <*>
+  [justifyLeft, justifyRight, center]

Task/Align-columns/Haskell/align-columns.hs

@@ -1,25 +0,0 @@
-import Data.List
-import Control.Monad
-import Control.Arrow
-
-dat = "Given$a$text$file$of$many$lines,$where$fields$within$a$line$\n" ++
-      "are$delineated$by$a$single$'dollar'$character,$write$a$program\n" ++
-      "that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$\n" ++
-      "column$are$separated$by$at$least$one$space.\n" ++
-      "Further,$allow$for$each$word$in$a$column$to$be$either$left$\n" ++
-      "justified,$right$justified,$or$center$justified$within$its$column.\n"
-
-brkdwn = takeWhile (not.null) . unfoldr (Just . second (drop 1) . span ('$'/=))
-
-format j ls = map (unwords. zipWith align colw) rows
-  where
-    rows = map brkdwn $ lines ls
-    colw = map (maximum. map length) . transpose $ rows
-    align cw w =
-      case j of
-        'c' -> (replicate l ' ') ++ w ++ (replicate r ' ')
-        'r' -> (replicate dl ' ') ++ w
-        'l' -> w ++ (replicate dl ' ')
-        where
-           dl = cw-length w
-           (l,r) = (dl `div` 2, dl-l)