A defsetf lambda list is used by defsetf.
A defsetf lambda list has the following syntax:
| lambda-list | ::= |
({var}*
[&optional {var | (var [init-form [supplied-p-parameter]])}*]
[&rest var]
[&key {var | ({var | (keyword-name var)} [init-form [supplied-p-parameter]])}* pt [&allow-other-keys]]
[&environment var]
|
A defsetf lambda list can contain the lambda list keywords shown in Figure 3–19.
&allow-other-keys &key &rest &environment &optional
A defsetf lambda list differs from an ordinary lambda list only in that it does not permit the use of &aux, and that it permits use of &environment, which introduces an environment parameter.