get-setf-expansion

(get-setf-expansion place &optional environment)

Returns the five setf-expansion values for place: a list of temporary variables, the list of value forms they bind, a list holding one store variable, the writer form, and the reader form. Lite: a variable place expands to a setq writer with no temporaries; an accessor form (f args...) binds one temporary per argument and writes through setf. The environment argument is accepted and ignored (a macro's &environment parameter is bound to nil). Consume the values with multiple-value-bind, as in the portable incf-style macro idiom.