diff --git a/lttb.tcl b/lttb.tcl
index 6c6a97b..827adf9 100755
--- a/lttb.tcl
+++ b/lttb.tcl
@@ -94,7 +94,7 @@ proc lttb_eval {lttb_ex} {
   if {[string is digit $lttb_ex]} {return [lttb_norm $(int($lttb_ex))]}
   lassign {{( 0 + 1 - 1 * 2 / 2 $ 3} {} {} {} {} 0} precmap valbuf prevc valstack opstack i
   set l [string length $lttb_ex]
-  loop i 0 $l {
+  for {set i 0} {$i < $l} {incr i} {
     set c [string index $lttb_ex $i]
     if [string is space $c] {continue}
     if [string is digit $c] {
@@ -105,7 +105,6 @@ proc lttb_eval {lttb_ex} {
         set valbuf {}
       }
       if {[string range $lttb_ex $i $($i+2)] eq {RND}} {
-        lappend valstack 0
         set c {$}
         incr i 2
       } elseif {[string is upper $c]} {