Subject: Re: setf'able? From: Erik Naggum <erik@naggum.no> Date: 1998/11/02 Newsgroups: comp.lang.lisp Message-ID: <3119024739483288@naggum.no> * Dobes Vandermeer <dobes@mindless.com> | How do you write functions that are "setf'able". | | i.e. | | (setf (myfunc myparams) 24) => Sets a special value "pointed to" in some | way by (myfunc myparams). others have answered with the code you need to write, but I'd like to change your view of setting and getting values, if I may. a variable (or a generalized place, in general) is something that yields a value that does not change from reference to reference (or call to call). "setting" the value of a variable (or a generalized place) is an "instruction" that it return that value until you "set" it again, as in "remember this!". if you think of this way, there are number of interesting and otherwise "read-only" places that you might want to return a different value. like, _setting_ the transatlantic round-trip time of IP datagrams -- your system could choose a different ISP, upgrade your links, move your office location, etc... :) #:Erik -- The Microsoft Dating Program -- where do you want to crash tonight?