extra data to supply to the callback function. these will be passed
as extra parameters after any provided by the parser.
void serror_cb(mapping(string:mixed) error, mixed ... extra_args);
mapping elements: domain, code, message, level, line, column
void entitydecl_cb(string name, int type, string publicId, string systemId, string content, mixed ... extra_args);
void elementdecl_cb(string name, int type, mixed ... extra_args);
void unparsedentitydecl_cb(string name, string publicId, string systemId, string notationName, mixed ... extra_args);
void attributedecl_cb(string elem, string fullname, int type, int def, string defaultValue, mixed ... extra_args);
void notationdecl_cb(string name, string publicId, string systemId, mixed ... extra_args);
void internalsubset_cb(string name, string ExternalId, string SystemId, mixed ... extra_args);
void externalsubset_cb(string name, string ExternalId, string SystemId, mixed ... extra_args);
void processinginstruction_cb(string target, string data, mixed ... extra_args);
void endelement_cb(string name, mixed ... extra_args);
void cdatablock_cb(string chars, mixed ... extra_args);
void ignorablewhitespace(string chars, mixed ... extra_args);
void characters_cb(string chars, mixed ... extra_args);
void reference_cb(string name, mixed ... extra_args);
void comment_cb(string value, mixed ... extra_args);
void startelement_cb(string name, mapping(string:string) attributes, mixed ... extra_args);
int isstandalone_cb(mixed ... extra_args);
void startdocument_cb(mixed ... extra_args);
void enddocument_cb(mixed ... extra_args);
int hasinternalsubset(mixed ... extra_args);
int hasexternalsubset(mixed ... extra_args);
string resolveentity(string publicId, string systemId, mixed ... extra_args);