binding ::= (type handler)
Each handler should evaluate to a handler-function, which is used to handle conditions of the given type during execution of the forms. This function should take a single argument, the condition being signaled.
If more than one handler binding is supplied, the handler bindings are searched sequentially from top to bottom in search of a match (by visual analogy with typecase). If an appropriate type is found, the associated handler is run in a dynamic environment where none of these handler bindings are visible (to avoid recursive errors). If the handler declines, the search continues for another handler.
In the following code, if an unbound variable error is signaled in the body (and not handled by an intervening handler), the first function is called.
If any other kind of error is signaled, the second function is called. In either case, neither handler is active while executing the code in the associated function.
(1 NIL 3)