sig
type xquery_error_msg =
Physical_value.item * Physical_value.item option *
Physical_value.item list
exception Xquery_error of Fn_error.xquery_error_msg
val raise_error :
Processing_context.processing_context -> Physical_value.item list -> 'a
val downgrade_error :
Processing_context.processing_context -> Fn_error.xquery_error_msg -> 'a
end