Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!rutgers!aramis.rutgers.edu!topaz.rutgers.edu!busboys.rutgers.edu!gaynor From: gaynor@busboys.rutgers.edu (Silver) Newsgroups: comp.lang.lisp Subject: Re: Are "destructive" functions really destructive? Message-ID: Date: 29 Nov 89 18:25:52 GMT References: <20991@mimsy.umd.edu> Distribution: usa Organization: Rutgers Univ., New Brunswick, N.J. Lines: 15 folta@tove.umd.edu writes: > [Concerning delete, is it destructive or what?] In the Reference, it says, > "..., or sequence may be unchanged and another sequence returned.", Although I'm not familiar with your reference, the problem may be a simple misunderstanding. What can be said about value returned by delete after removing 1 from the following list? L --> (1 -2 3 -5 8 -13) In this case, it appears reasonable for delete to simply return the cdr of L. So, L (that is, the list referenced by L) is unchanged, and a list that is not L (namely, L's cdr) is being returned. Awkward? Naw. Ok, well, maaaybe. Happy Hunting, [Ag]