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|
(* $Id$
* ----------------------------------------------------------------------
*
*)
(**********************************************************************)
(* Examples for pull parsing *)
(**********************************************************************)
open Pxp_ev_parser
open Pxp_lexer_types
open Pxp_types
open Printf
(* dump_event: dumps a single parsing event *)
let dump_event e =
print_endline (Pxp_event.string_of_event e)
;;
(* parse: prints the events while parsing the passed string *)
let parse s =
let config = default_config in
let mgr = create_entity_manager config (from_string s) in
let next_event =
create_pull_parser config (`Entry_content[]) mgr in
let event = ref (Some E_end_of_stream) in
while !event <> None do
event := next_event();
match !event with
Some e -> dump_event e
| None -> ()
done
;;
(* Stream parsers:
* parse_list
* "<list><cons><int>34</int><cons><int>67</int><nil/></cons></cons></list>"
* = [34; 67]
*)
let parse_list s =
let rec parse_whole_list stream =
match stream with parser
[< 'E_start_tag("list",_,_,_);
l = parse_sub_list;
'E_end_tag("list",_);
'E_end_of_stream;
>] ->
l
and parse_sub_list stream =
match stream with parser
[< 'E_start_tag("cons",_,_,_);
head = parse_object;
tail = parse_sub_list;
'E_end_tag("cons",_)
>] ->
head :: tail
| [< 'E_start_tag("nil",_,_,_); 'E_end_tag("nil",_) >] ->
[]
and parse_object stream =
match stream with parser
[< 'E_start_tag("int",_,_,_);
number = parse_text;
'E_end_tag("int",_)
>] ->
int_of_string number
and parse_text stream =
match stream with parser
[< 'E_char_data data;
rest = parse_text
>] ->
data ^ rest
| [< >] ->
""
in
let config =
{ default_config with
store_element_positions = false;
(* don't produce E_position events *)
}
in
let mgr = create_entity_manager config (from_string s) in
let next_event =
create_pull_parser config (`Entry_content[]) mgr in
let next_event_or_error _ =
let e = next_event () in
match e with
Some(E_error exn) -> raise exn
| _ -> e
in
let stream =
Stream.from next_event_or_error in
parse_whole_list stream
;;
|
