diff --git a/lume.lua b/lume.lua
index 6c40fef..2160f97 100644
--- a/lume.lua
+++ b/lume.lua
@@ -231,7 +231,7 @@ end
 
 
 function lume.format(str, vars)
-  local f = function(x) return tostring(vars[x]) or "{" .. x .. "}" end
+  local f = function(x) return tostring(vars[x] or "{" .. x .. "}") end
   return (str:gsub("{(.-)}", f))
 end