]> Sorry for the late reply. On Wed, Sep 30, 2009 at 01:00:15AM +0200, Mikkel Fahnøe Jørgensen wrote: > Otherwise there is xmlm which is self-contained in single xml file, > and as I recall, has some sort of zipper navigator. (I initially > intended to use it before deciding on the json format): The cursor api was removed from the library in 1.0.0. On Wed, Sep 30, 2009 at 6:16 PM, Richard Jones <rich@annexia.org> wrote: > It's interesting you mention xmlm, because I couldn't write > the code using xmlm at all. Why ? That doesn't feel like an insurmontable task. Below is a function that extracts from a (sub)tree's sequence of signals the attributes' data of an absolute path (i.e. the particular xpath pattern you're after if I understand correctly). Each attribute's data is stored in a separate list. The function is simpler than it looks, in essence it's just a recursive case analysis on signals. In the function [aux], [pos] maintains the current path in the parse tree. [mismatch] counts the level of mismatch w.r.t. the [path] we are looking for. let absolute_path_atts i path atts = let rec aux i pos mismatch path accs = match Xmlm.input i with | `El_start (tag, atts) -> if mismatch > 0 then aux i (tag :: pos) (mismatch + 1) path accs else begin match path with | n :: path' when n = tag -> if path' <> [] then aux i (tag :: pos) 0 path' accs else let update_acc ((att, acc) as v) = try att, (List.assoc att atts) :: acc with Not_found -> v in aux i (tag :: pos) 0 [] (List.map update_acc accs) | _ -> aux i (tag :: pos) (mismatch + 1) path accs end | `El_end -> begin match pos with | _ :: [] -> List.rev_map (fun (att, acc) -> List.rev acc) accs | tag :: pos' -> if mismatch > 0 then aux i pos' (mismatch - 1) path accs else aux i pos' 0 (tag :: path) accs | [] -> assert false end | `Data _ -> aux i pos mismatch path accs | `Dtd _ -> assert false in let accs = List.rev_map (fun att -> att, []) atts in begin match Xmlm.peek i with | `El_start _ -> aux i [] 0 path accs | `Dtd _ | `El_end | `Data _ -> invalid_arg "no subtree here" end Now your function becomes something like this : let get_devices_from_xml xml = try let i = Xmlm.make_input (`String (0, xml)) in ignore (Xmlm.input i); (* `Dtd signal *) let path = ["", "domain"; "","devices"; "", "disk"; "", "source"] in match absolute_path_atts i path ["", "dev"; "", "file"] with | [devs; files] when Xmlm.eoi i -> devs @ files | _ -> failwith "xml document not well-formed" with | Xmlm.Error ((l,c), e) -> failwith (Printf.sprintf "%d:%d: %s" l c (Xmlm.error_message e)) I know this is still more effort than you'd like, but Xmlm is purposedly low-level and will remain. It provides only a robust xmlm parser convenient (I believe) to develop higher-level abstractions to process the insane uses of this standard. It would be nice to develop a module using xmlm to provide a (non-camlp4) dsl for xml queries. Unfortunately I do not have the time for that at the moment (unless someone wants to fund me to do that...). Best, Daniel