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]])}* [&allow-other-keys]] 
                [&environment var] 

A defsetf lambda list can contain the lambda list keywords shown in the next figure.

&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.