diff --git a/lib/Quox/Syntax/Term/Pretty.idr b/lib/Quox/Syntax/Term/Pretty.idr
index a980f02..e34a1c3 100644
--- a/lib/Quox/Syntax/Term/Pretty.idr
+++ b/lib/Quox/Syntax/Term/Pretty.idr
@@ -53,10 +53,13 @@ prettyLams sort names body = do
 
 export covering
 prettyApps : PrettyHL f => PrettyHL a => Pretty.HasEnv m =>
-             f -> List a -> m (Doc HL)
-prettyApps fun args =
+             Maybe (Doc HL) -> f -> List a -> m (Doc HL)
+prettyApps pfx fun args =
   parensIfM App =<< withPrec Arg
-    [|prettyM fun <//> (align . sep <$> traverse prettyM args)|]
+    [|prettyM fun <//> (align . sep <$> traverse prettyArg args)|]
+ where
+  prettyArg : a -> m (Doc HL)
+  prettyArg x = maybe id (\p => map (hl Delim p <+>)) pfx $ prettyM x
 
 export covering
 prettyTuple : PrettyHL a => Pretty.HasEnv m => List a -> m (Doc HL)
@@ -141,7 +144,7 @@ mutual
       prettyVar TVar TVarErr (!ask).tnames i
     prettyM (e :@ s) =
       let GotArgs {fun, args, _} = getArgs' e [s] in
-      prettyApps fun args
+      prettyApps Nothing fun args
     prettyM (CasePair pi p (S [r] ret) (S [x, y] body)) = do
       pat <- (parens . separate commaD . map (hl TVar)) <$>
              traverse prettyM [x, y]
@@ -151,7 +154,7 @@ mutual
         [([], prettyTag t, b) | (t, b) <- SortedMap.toList arms]
     prettyM (e :% d) =
       let GotDArgs {fun, args, _} = getDArgs' e [d] in
-      prettyApps fun args
+      prettyApps (Just "@") fun args
     prettyM (s :# a) =
       parensIfM Ann $ hang 2 $
         !(withPrec AnnL $ prettyM s) <++> !annD