Markup: make markup support multi-line strings (fixes #41)

programs/MarkupDemo.hs

@@ -7,9 +7,12 @@ import qualified Graphics.Vty as V
 import Brick.Main (App(..), defaultMain, resizeOrQuit, neverShowCursor)
 import Brick.Types
   ( Widget
+  , Padding(..)
   )
 import Brick.Widgets.Core
   ( (<=>)
+  , (<+>)
+  , padLeft
   )
 import Brick.Util (on, fg)
 import Brick.Markup (markup, (@?))
@@ -17,10 +20,11 @@ import Brick.AttrMap (attrMap, AttrMap)
 import Data.Text.Markup ((@@))
 
 ui :: Widget
-ui = m1 <=> m2
+ui = (m1 <=> m2) <+> (padLeft (Pad 1) m3)
     where
         m1 = markup $ ("Hello" @@ fg V.blue) <> ", " <> ("world!" @@ fg V.red)
         m2 = markup $ ("Hello" @? "keyword1") <> ", " <> ("world!" @? "keyword2")
+        m3 = markup $ ("Hello," @? "keyword1") <> "\n" <> ("world!" @? "keyword2")
 
 theMap :: AttrMap
 theMap = attrMap V.defAttr

src/Brick/Markup.hs

@@ -17,7 +17,7 @@ import qualified Data.Text as T
 import Data.Text.Markup
 import Data.Default (def)
 
-import Graphics.Vty (Attr, horizCat, string)
+import Graphics.Vty (Attr, vertCat, horizCat, string)
 
 import Brick.AttrMap
 import Brick.Types
@@ -47,8 +47,11 @@ instance GetAttr AttrName where
 markup :: (Eq a, GetAttr a) => Markup a -> Widget
 markup m =
     Widget Fixed Fixed $ do
-      let pairs = markupToList m
+      let markupLines = markupToList m
-      imgs <- forM pairs $ \(t, aSrc) -> do
+          mkLine pairs = do
+              is <- forM pairs $ \(t, aSrc) -> do
                   a <- getAttr aSrc
                   return $ string a $ T.unpack t
-      return $ def & imageL .~ horizCat imgs
+              return $ horizCat is
+      lineImgs <- mapM mkLine markupLines
+      return $ def & imageL .~ vertCat lineImgs

src/Data/Text/Markup.hs

@@ -45,7 +45,7 @@ fromText = (@@ def)
 
 -- | Extract the text from markup, discarding the markup metadata.
 toText :: (Eq a) => Markup a -> T.Text
-toText = T.concat . (fst <$>) . markupToList
+toText = T.concat . (fst <$>) . concat . markupToList
 
 -- | Set the metadata for a range of character positions in a piece of
 -- markup. This is useful for, e.g., syntax highlighting.
@@ -59,11 +59,17 @@ markupSet (start, len) val m@(Markup l) = if start < 0 || start + len > length l
         (theOldEntries, theTail) = splitAt len theLongTail
         theNewEntries = zip (fst <$> theOldEntries) (repeat val)
 
--- | Convert markup to a list of pairs in which each pair contains the
+-- | Convert markup to a list of lines. Each line is represented by a
--- longest subsequence of characters having the same metadata.
+-- list of pairs in which each pair contains the longest subsequence of
-markupToList :: (Eq a) => Markup a -> [(T.Text, a)]
+-- characters having the same metadata.
-markupToList (Markup thePairs) = toList thePairs
+markupToList :: (Eq a) => Markup a -> [[(T.Text, a)]]
+markupToList (Markup thePairs) = toList <$> toLines [] [] thePairs
     where
+        toLines ls cur [] = ls ++ [cur]
+        toLines ls cur ((ch, val):rest)
+            | ch == '\n' = toLines (ls ++ [cur]) [] rest
+            | otherwise = toLines ls (cur ++ [(ch, val)]) rest
+
         toList [] = []
         toList ((ch, val):rest) = (T.pack $ ch : (fst <$> matching), val) : toList remaining
             where