diff --git a/nix-script.hs b/nix-script.hs
index 3d82a83..cc7fb03 100755
--- a/nix-script.hs
+++ b/nix-script.hs
@@ -8,9 +8,13 @@ import System.Environment           (lookupEnv, getProgName, getArgs)
 import System.Process               (callProcess)
 import System.Posix.Escape.Unicode  (escapeMany)
 
-
+-- | Enviroment variables
 type Env   = [String]
+
+-- | Program arguments
 type Args  = [String]
+
+-- | interpreter name and arguments
 type Inter = (String, Args)