Define a more aesthetic Show instance for Bindings.

src/Data/Abstract/Environment.hs

@@ -36,7 +36,7 @@ import           Prologue
 
 -- | A map of names to values. Represents a single scope level of an environment chain.
 newtype Bindings address = Bindings { unBindings :: Map.Map Name address }
-  deriving (Eq, Ord, Show)
+  deriving (Eq, Ord)
 
 instance Semigroup (Bindings address) where
   (<>) (Bindings a) (Bindings b) = Bindings (a <> b)
@@ -48,6 +48,9 @@ instance Monoid (Bindings address) where
 instance Lower (Bindings address) where
   lowerBound = mempty
 
+instance Show address => Show (Bindings address) where
+  showsPrec d = showsUnaryWith showsPrec "Bindings" d . pairs
+
 -- | A LIFO stack of maps of names to addresses, representing a lexically-scoped evaluation environment.
 --   All behaviors can be assumed to be frontmost-biased: looking up "a" will check the most specific
 --   scope for "a", then the next, and so on.