diff --git a/lists.cabal b/lists.cabal
--- a/lists.cabal
+++ b/lists.cabal
@@ -1,5 +1,5 @@
 name:                lists
-version:             0.4.0
+version:             0.4.1
 synopsis:            Functions for dealing with lists
 description:         Functions for dealing with lists
 license:             BSD3
diff --git a/src/Lists.hs b/src/Lists.hs
--- a/src/Lists.hs
+++ b/src/Lists.hs
@@ -45,7 +45,7 @@
 -- | When a list is non-null, pass it to a function, otherwise use the
 -- default.
 list :: b -> ([a] -> b) -> [a] -> b
-list nil cons = cond (const nil) cons null
+list nil cons = cond (const nil) cons (not . null)
 
 -- | Get the union of the given lists.
 unionOf :: (Eq a) => [[a]] -> [a]