unlist <- function(x, recursive=TRUE, use.names=TRUE)
{
    if(.Internal(islistfactor(x, recursive))) {
        lv <- unique(.Internal(unlist(lapply(x, levels), recursive, FALSE)))
        nm <- if(use.names) names(.Internal(unlist(x, recursive, use.names)))
        res <- .Internal(unlist(lapply(x, as.character), recursive, FALSE))
        res <- match(res, lv)
        ## we cannot make this ordered as level set may have been changed
        structure(res, levels=lv, names=nm, class="factor")
    } else .Internal(unlist(x, recursive, use.names))
}