> changes
function (x, y)
{
    x <- location(x)
    y <- location(y)
    if (x$df == y$df) {
        cat("<identical>\n")
        return(invisible())
    }
    vars <- match_up(x$vars, y$vars)
    attr <- match_up(x$attr, y$attr)
    width <- max(nchar(rownames(vars)), nchar(rownames(attr)))
    if (nrow(vars) > 0)
        rownames(vars) <- format(rownames(vars), width = width)
    if (nrow(attr) > 0)
        rownames(attr) <- format(rownames(attr), width = width)
    if (nrow(vars) > 0) {
        cat("Changed variables:\n")
        print(vars, quote = FALSE)
    }
    if (nrow(vars) > 0 && nrow(attr))
        cat("\n")
    if (nrow(attr) > 0) {
        cat("Changed attributes:\n")
        print(attr, quote = FALSE)
    }
}
<environment: namespace:dplyr>