Global Identifiers (root only):
there are 4 classes of global identifiers.

First Class: 
 
   Control Identifiers
   
   let
   if
   while
   
   else
   return
   dbg
   
   order

Second Class:

   Global Variables:
   null
   time
   rand
   
   e
   ln2
   clock
   
   sys
   m
   pi
   
   
   
   

Third Class:
