Common Lisp the Language, 2nd Edition

28.1.6.3. Agreement on Parameter Specializers and Qualifiers

Two methods are said to agree with each other on parameter specializers and qualifiers if the following conditions hold:

• Both methods have the same number of required parameters. Suppose the parameter specializers of the two methods are and .

• For each 1 <= i <= n, agrees with . The parameter specializer agrees with if and are the same class or if , , and (eql ). Otherwise and do not agree.

• The lists of qualifiers of both methods contain the same non-nil atoms in the same order. That is, the lists are equal.