sub..endsub group
   sub - Begin subroutine
   endsub - End subroutine
   return - Exit subroutine
   call - Call subroutine

  do..while group
   do - Begin block
   while - End block
   break - Exit block immediately
   continue - Skip to next condition evaluation

  while..endwhile group
   while - Begin block
   endwhile - End block
   break - Exit block immediately
   continue - Skip to next condition evaluation

  repeat..endrepeat group
   repeat - Begin block
   endrepeat - End block

  if..endif group
   if - Begin block
   endif - End block
   elseif - Else
   else - Else