Macro Request-Hook

Part of:

package weblocks
( request-hook &rest < args > )
Allows access to a series of hooks exposed by 'handle-client-request'.

scope - the scope of the hook. Can be set to :application, :session,
or :request. An :application hook is maintained throughout the
lifetime of the entire application. A :session hook is destroyed along
with the session. A :request hook is only valid for the request.

location - the location of the hook. Can be set
to :pre-action, :post-action, :pre-render, and :post-render.

The macro returns a place that can be used to push a callback function
of no arguments.