diff --git a/global-functions.rsc b/global-functions.rsc
index f870df18..37e297a8 100644
--- a/global-functions.rsc
+++ b/global-functions.rsc
@@ -306,12 +306,18 @@
 
   :for I from=0 to=([ :len $Input ] - 1) do={
     :local Char [ :pick $Input $I ];
-    :if ([ :typeof [ :find "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" $Char ] ] = "nil") do={
-      :if ([ :len $Return ] = 0 || \
-           [ :pick $Return ([ :len $Return ] - 1) ] = "-") do={
-        :continue;
+    :if ([ :typeof [ find "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789" $Char ] ] = "nil") do={
+      :do {
+        :if ([ :len $Return ] = 0) do={
+          :error true;
+        }
+        :if ([ :pick $Return ([ :len $Return ] - 1) ] = "-") do={
+          :error true;
+        }
+        :set Char "-";
+      } on-error={
+        :set Char "";
       }
-      :set Char "-";
     }
     :set Return ($Return . $Char);
   }