Improve forcefield visuals

src/FoldableHelp.hs

@@ -5,6 +5,7 @@ module FoldableHelp
     , safeMinimumOnMaybeF
     , safeMinimumOnMaybeL
     , safeMinMaybeL
+    , filter3
     , module Data.Foldable
     )
     where
@@ -62,6 +63,16 @@ safeMinimumOnMaybe f ys = fst <$> go Nothing ys
         _                 -> go (Just (y,cmin)) xs
     go m _ = m
 
+filter3 :: Foldable t 
+    => (a -> Bool) 
+    -> (a -> Bool) 
+    -> (a -> Bool)
+    -> t a
+    -> ([a],[a],[a])
+filter3 t1 t2 t3 = L.fold $ (,,) 
+    <$> L.prefilter t1 L.list 
+    <*> L.prefilter t2 L.list
+    <*> L.prefilter t3 L.list
 
 --{- | Partial. -}
 --minimumOn :: Ord b => (a -> b) -> [a] -> a