diff --git a/trie.lua b/trie.lua
index 1231fa1..3399b69 100644
--- a/trie.lua
+++ b/trie.lua
@@ -7,6 +7,8 @@ setfenv(1, _ENV)
 
 local metatable = {__index = _ENV}
 
+-- Setting the metatable is fine as it does not contain single-character keys.
+-- TODO (?) encapsulate in "root" field for better code quality?
 function new(table) return setmetatable(table or {}, metatable) end
 
 function insert(self, word, value, overwrite)