Move towards displaying tree links in inventory

src/FoldableHelp.hs

@@ -10,6 +10,7 @@ module FoldableHelp
     , ssfold
     , minOn
     , module Data.Foldable
+    , minAndMax
     )
     where
 import Data.Foldable
@@ -105,3 +106,5 @@ ssfold :: Foldable t => (a -> Bool) -> (a -> b -> a) -> a -> t b -> a
 {-# INLINABLE ssfold #-}
 ssfold p f a0 xs = foldr (\x g a -> if p a then a else g (f a x)) id xs a0
 
+minAndMax :: (Foldable t,Ord a) => t a -> (Maybe a,Maybe a)
+minAndMax = L.fold ((,) <$> L.minimum <*> L.maximum)