[Ocaml-pxp-users] How do I resolve PUBLIC external entities from inside DTD files?

Thu May 14 00:28:14 PDT 2009

I'm trying to work out how to use PXP, so I've written a toy program to read XHTML 
files. It resolves PUBLIC id's to files in the current directory, where I've placed 
W3C's XHTML DTD files. It can open the DTD file from inside an XHTML file, but it 
does not open PUBLIC entity files from within the DTD. I've attached the program 
and the error that comes up. Please, could anyone tell what I'm doing wrong?

 ************************************************************
glyn at ela:~/Ocamldtd/Test$ ls
pxptest.ml  xhtml1-transitional-2.dtd  xhtml-lat1.ent     xhtml-symbol.ent
test.html   xhtml1-transitional.dtd    xhtml-special.ent

glyn at ela:~/Ocamldtd/Test$ ocamlfind ocamlc -package pxp -linkpkg pxptest.ml && ./a.out
In entity [toplevel] = SYSTEM "file://localhost/home/glyn/Ocamldtd/Test/test.html", at line 4, position 64:
In entity [dtd] = PUBLIC "-//W3C//DTD XHTML 1.0 Transitional" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd", at line 29, position 
0:
ERROR: Unable to open the external entity: HTMLlat1 = PUBLIC "-//W3C//ENTITIES Latin 1 for XHTML//EN" "xhtml-lat1.ent"

 ************************************************************
 pxptest.ml

let catalog =
  new Pxp_reader.lookup_public_id_as_file
    [ ("-//W3C//DTD XHTML 1.0 Transitional",		"xhtml1-transitional.dtd");
      ("-//W3C//ENTITIES Latin 1 for XHTML//EN",   	"xhtml-lat1.ent");
      ("-//W3C//ENTITIES Symbols 1 for XHTML//EN", 	"xhtml-symbol.ent");
      ("-//W3C//ENTITIES Special 1 for XHTML//EN", 	"xhtml-special.ent") ]
;;

try
  let document = 
    Pxp_tree_parser.parse_document_entity 
      Pxp_types.default_config
      (Pxp_types.from_file ~alt:[catalog] "test.html")
      Pxp_tree_parser.default_spec
  in
  document # root # write (`Out_channel stdout) `Enc_utf8
with exn ->
  print_endline (Pxp_types.string_of_exn exn)
;;

 ************************************************************
 test.html

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC
       "-//W3C//DTD XHTML 1.0 Transitional"
       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
    <head>
    ...etc...

--Glyn