exception Invalid_RDF_class of string
exception Internal_error of string
exception Cache_failure of string
+exception Dtd_not_found of string (* dtd's url *)
+exception Key_already_in of string;;
+exception Key_not_found of string;;
-type encoding = Enc_normal | Enc_gzipped
-type answer_format = Fmt_text | Fmt_xml
+type encoding = [ `Normal | `Gzipped ]
+type answer_format = [ `Text | `Xml ]
type ls_flag = No | Yes | Ann
type ls_object =
{