static VALUE from_document(int argc, VALUE *argv, VALUE klass)
{
  VALUE document;
  VALUE parse_options;
  xmlDocPtr doc;
  xmlRelaxNGParserCtxtPtr ctx;
  xmlRelaxNGPtr schema;
  VALUE errors;
  VALUE rb_schema;
  int scanned_args = 0;

  scanned_args = rb_scan_args(argc, argv, "11", &document, &parse_options);

  Data_Get_Struct(document, xmlDoc, doc);
  doc = doc->doc; /* In case someone passes us a node. ugh. */

  if (scanned_args == 1) {
    parse_options = rb_const_get(rb_const_get(mNokogiriXml, rb_intern("ParseOptions")), rb_intern("DEFAULT_SCHEMA"));
  }

  ctx = xmlRelaxNGNewDocParserCtxt(doc);

  errors = rb_ary_new();
  xmlSetStructuredErrorFunc((void *)errors, Nokogiri_error_array_pusher);

#ifdef HAVE_XMLRELAXNGSETPARSERSTRUCTUREDERRORS
  xmlRelaxNGSetParserStructuredErrors(
    ctx,
    Nokogiri_error_array_pusher,
    (void *)errors
  );
#endif

  schema = xmlRelaxNGParse(ctx);

  xmlSetStructuredErrorFunc(NULL, NULL);
  xmlRelaxNGFreeParserCtxt(ctx);

  if(NULL == schema) {
    xmlErrorPtr error = xmlGetLastError();
    if(error)
      Nokogiri_error_raise(NULL, error);
    else
      rb_raise(rb_eRuntimeError, "Could not parse document");

    return Qnil;
  }

  rb_schema = Data_Wrap_Struct(klass, 0, dealloc, schema);
  rb_iv_set(rb_schema, "@errors", errors);
  rb_iv_set(rb_schema, "@parse_options", parse_options);

  return rb_schema;
}
static VALUE from_document(int argc, VALUE *argv, VALUE klass)
{
  VALUE document;
  VALUE parse_options;
  xmlDocPtr doc;
  xmlRelaxNGParserCtxtPtr ctx;
  xmlRelaxNGPtr schema;
  VALUE errors;
  VALUE rb_schema;
  int scanned_args = 0;

  scanned_args = rb_scan_args(argc, argv, "11", &document, &parse_options);

  Data_Get_Struct(document, xmlDoc, doc);
  doc = doc->doc;  

  if (scanned_args == 1) {
    parse_options = rb_const_get(rb_const_get(mNokogiriXml, rb_intern("ParseOptions")), rb_intern("DEFAULT_SCHEMA"));
  }

  ctx = xmlRelaxNGNewDocParserCtxt(doc);

  errors = rb_ary_new();
  xmlSetStructuredErrorFunc((void *)errors, Nokogiri_error_array_pusher);

#ifdef HAVE_XMLRELAXNGSETPARSERSTRUCTUREDERRORS
  xmlRelaxNGSetParserStructuredErrors(
    ctx,
    Nokogiri_error_array_pusher,
    (void *)errors
  );
#endif

  schema = xmlRelaxNGParse(ctx);

  xmlSetStructuredErrorFunc(NULL, NULL);
  xmlRelaxNGFreeParserCtxt(ctx);

  if(NULL == schema) {
    xmlErrorPtr error = xmlGetLastError();
    if(error)
      Nokogiri_error_raise(NULL, error);
    else
      rb_raise(rb_eRuntimeError, "Could not parse document");

    return Qnil;
  }

  rb_schema = Data_Wrap_Struct(klass, 0, dealloc, schema);
  rb_iv_set(rb_schema, "@errors", errors);
  rb_iv_set(rb_schema, "@parse_options", parse_options);

  return rb_schema;
}