diff --git a/TODO b/TODO
index 929ccca..679c413 100644
--- a/TODO
+++ b/TODO
@@ -4,6 +4,12 @@ Big Goals
 
 Tasks/Bugs:
 
+* empty expr should die:
+
+% expr ""
+empty expression
+in expression ""
+
 * regexp $re $str (blocker for t/tcl_time.t)
 * regsub -all <exp> <string> <replace>
 * Need to throw an exception when trying to convert something to an