Add link types to attachment tree

src/Dodge/Data/DoubleTree.hs

@@ -8,13 +8,21 @@ module Dodge.Data.DoubleTree
 import Control.Lens
 import Data.Aeson
 import Data.Aeson.TH
+import Data.Bifunctor
 
 
 data DoubleTree a = DT {_dtValue :: a,_dtLeft :: [DoubleTree a],_dtRight :: [DoubleTree a]}
     deriving (Eq,Ord,Show,Read)
 
+data LabelDoubleTree b a = LDT {_ldtValue :: a, _ldtLeft :: [(b,LabelDoubleTree b a)]
+        ,_ldtRight :: [(b,LabelDoubleTree b a)]}
+    deriving (Eq,Ord,Show,Read)
+
 instance Functor DoubleTree where
     fmap f (DT x l r) = DT (f x) (fmap (fmap f) l) (fmap (fmap f) r)
 
+instance Functor (LabelDoubleTree b) where
+    fmap f (LDT x l r) = LDT (f x) (fmap (second $ fmap f) l) (fmap (second $ fmap f) r)
+
 makeLenses ''DoubleTree
 deriveJSON defaultOptions ''DoubleTree