When a generic procedure is called, it arranges to invoke a subset of
its methods. This is done by combining the selected methods into
an effective method procedure, or EMP, then tail-recursively
invoking the EMP.
compute-effective-method-procedure is the
procedure that is called to select the applicable methods and combine
them into an EMP.
Collects the applicable methods of generic-procedure by calling
method-applicable? on each method and on classes. Combines
the resulting methods together into an effective method procedure, and
returns that EMP.
This procedure is like
that it returns the result as a method whose specializers are
compute-method is equivalent to
(make-method classes (compute-effective-method-procedure generic-procedure classes))