======Using Hooks with Serial Numbers======

One of the neat things about [[ON]] hooks is that multiple hooks of the same
type may be given different priorities.  A serial number may be any number,
positive or negative; zero is the default and should not be used directly.
The numbers themselves don't really matter, rather their relation to other
serial numbers is what's important.  For example:

   on   hook    "*" echo foobar
   on #-hook -5 "*" echo booya
   on #-hook  5 "*" echo yadda yadda yadda

Then, when any [[HOOK]] command is issued, the following three lines will be
displayed, in this order:

   booya
   foobar
   yadda yadda yadda

In general, it is always advisable to use serial numbers, if for no other
reason than to prevent hooks from conflicting with each other. This is
particularly true of the [[TIMER]] hook, which should always use serial
numbers.