Merge pull request #354 from pcapriotti/topic/improve-readability

Improve readability of help text

src/Options/Applicative/Help/Core.hs

@@ -112,7 +112,7 @@ briefDesc' showOptional pprefs
       , descHidden = False }
 
 -- | Wrap a doc in parentheses or brackets if required.
-wrap :: AltNodeType ->  (Chunk Doc, Wrapping) -> Chunk Doc
+wrap :: AltNodeType -> (Chunk Doc, Wrapping) -> Chunk Doc
 wrap altnode (chunk, wrapping)
   | altnode == MarkDefault
   = fmap brackets chunk
@@ -130,11 +130,13 @@ foldTree (MultNode xs)
   = (foldr ((<</>>) . wrap NoDefault . foldTree) mempty xs, Bare)
 foldTree (AltNode b xs)
   = (\x -> (x, Bare))
+  . fmap groupOrLine
   . wrap b
   . alt_node
   . filter (not . isEmpty . fst)
   . map foldTree $ xs
     where
+
   alt_node :: [(Chunk Doc, Wrapping)] -> (Chunk Doc, Wrapping)
   alt_node [n] = n
   alt_node ns = (\y -> (y, Wrapped))

src/Options/Applicative/Help/Pretty.hs

@@ -1,10 +1,35 @@
 module Options.Applicative.Help.Pretty
   ( module Text.PrettyPrint.ANSI.Leijen
   , (.$.)
+  , groupOrLine
   ) where
 
-import Text.PrettyPrint.ANSI.Leijen hiding ((<$>), (<>), columns)
+import           Control.Applicative
+import           Data.Monoid (mappend)
+
+import           Text.PrettyPrint.ANSI.Leijen hiding ((<$>), (<>), columns)
+import           Text.PrettyPrint.ANSI.Leijen.Internal (Doc (..), flatten)
 import qualified Text.PrettyPrint.ANSI.Leijen as PP
 
+import           Prelude
+
 (.$.) :: Doc -> Doc -> Doc
 (.$.) = (PP.<$>)
+
+-- | Apply the funcion if we're not at the
+--   start of our nesting level.
+ifNotAtRoot :: (Doc -> Doc) -> Doc -> Doc
+ifNotAtRoot f doc =
+  Nesting $ \i ->
+    Column $ \j ->
+      if i == j
+        then doc
+        else f doc
+
+-- | Render flattened text on this line, or start
+--   a new line before rendering any text.
+groupOrLine :: Doc -> Doc
+groupOrLine =
+  Union
+    <$> flatten
+    <*> ifNotAtRoot (mappend line)