&REST lists

[Glenn S. Burke <gsb@JASPER.Palladian.COM>]

    Date: Mon, 4 Jan 1988  20:27 EST
    From: "Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>


	Is there general agreement on whether it is valid Common Lisp to
	destructively modify (RPLACA, RPLACD) the list to which a &REST
	parameter is bound?  I can't find a reference in CLtL for this.

    I think there's general agreement that &rest args are supposed to be
    righteous lists with indefinite extent, so RPLAC'ing them ought to be
    legal.

I think it is legal for APPLY to pass user-specified list structure to
the function; if so the &REST list should be treated as read-only, as it
well might be.  I can't remember this for sure.