]> On Thursday 05 December 2002 12:47 pm, Oleg wrote: > let rec (@) l1 l2 = > match l1 with > [] -> l2 > > | hd :: tl -> hd :: (tl @ l2) > > The O'Caml implementation of (@) is recursive and not tail-recursive. All > one really has to do during "append" is copy l1 and set the last element's > CDR to l2. I can see why this can not be done in O'Caml itself, but since > (@) is such a common operation, I'm wondering why it was decided to > implement it inefficently in O'Caml itself? You say you want to copy l1 and then set the last element of tail to l2? But, that is _exactly_ what the function above does! let copy l1 = match l1 with [] -> [] | hd :: tl -> hd :: copy tl Right? So, the only change is the extra argument l2, that is being appended onto the list when l1 is empty. PKE. -- _ \`. Pål-Kristian Engstad, Senior Software Engineer, \ `| Naughty Dog, Inc., 1315 3rd Street Promenade, __\ |`. Santa Monica, CA 90046, USA. (310) 752-1000 x799. / /o mailto:engstad@naughtydog.com http://www.naughtydog.com / '~ mailto:mrengstad@yahoo.com http://www.engstad.com / ,' Hang-gliding Rulez! ~' ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners