3.4.7 Defsetf Lambda Lists

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         

  Figure 3–19: Lambda List Keywords used by Defsetf Lambda Lists

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.