diff --git a/.gitignore b/.gitignore
index cff341c..735a38e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,4 @@
-/tutorial.md
-/.stack-work/
+.stack-work/
 .lish-history
 *.tix
 stack.yaml.lock
diff --git a/src/Lish/Eval.hs b/src/Lish/Eval.hs
index 89d8f0c..fdaa6e2 100644
--- a/src/Lish/Eval.hs
+++ b/src/Lish/Eval.hs
@@ -85,8 +85,8 @@ _reduceLambda (Atom x) = do
     Just s -> return s
     _      -> case InternalCommands.lookup x of
       Just cmd -> return (Internal cmd)
-      _         -> return (Str x)
-_reduceLambda x          = return x
+      _        -> return (Str x)
+_reduceLambda x = return x
 
 reduceLambda :: SExp -> StateT Env IO SExp
 reduceLambda x = do
diff --git a/src/Lish/Types.hs b/src/Lish/Types.hs
index f5663b0..d82ce91 100644
--- a/src/Lish/Types.hs
+++ b/src/Lish/Types.hs
@@ -27,13 +27,14 @@ import           GHC.IO.Handle   (Handle)
 import           GHC.Show        (Show (..))
 import           Protolude       hiding (show,repr)
 
-data ExprF a = Atom Text
-             | Num Integer
-             | Bool Bool
-             | Str Text
-             | List [a]
-             | Lambda [a]
-             | Void
+-- | Type representing an expression
+data ExprF a = Atom Text -- ^ an atom is just a variable name
+             | Num Integer -- ^ a number
+             | Bool Bool -- ^ a boolean
+             | Str Text -- ^ a string
+             | List [a] -- ^ a list
+             | Lambda [a] -- ^ a function (lambda expression)
+             | Void -- ^ an empty value
               -- only exists during evaluation
              | Internal InternalCommand
              | Fn { params  :: [Text]