define-modify-macro

(define-modify-macro name (parameter...) function [documentation])

Defines a macro name so that (name place argument...) expands to (setf place (function place argument...)) -- a read-modify-write of place through function. A trailing &rest parameter is spliced into the call. Lite: the place subforms may be evaluated more than once (no get-setf-expansion single-evaluation protocol) and the optional documentation string is ignored.