&REST lists

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

    Date: Tue, 5 Jan 88 10:59 EST
    From: Barry Margolin <barmar@Think.COM>

	Date: Tue, 5 Jan 88 02:12 EST
	From: Glenn S. Burke <gsb@jasper.palladian.com>

	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.

    That doesn't follow.  Just because you pass a read-only list to APPLY
    doesn't mean that it has to use that same list when it invokes the
    function.  APPLY could COPY-LIST it.  Or in an implementation that uses
    stack-consed &REST args the list elements might be copied to the stack.

						    barmar

You miss the point entirely.  I am saying that if it is a permissible
implementation for apply to NOT copy a user-specified list, then proper
coding practice would be to not modify &rest lists.

I don't know or remember if APPLY is permitted to do this.  This came up
back when the original stack-list/heap-list decision was made, and there
may have been a consensus on it at the time.