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#' @title
#' Ensure that R expressions are false
#'
#' @description
#' If any of the expressions in \code{...} are not all \code{FALSE},
#' stop is called, producing an error message indicating
#' the first of the elements of \code{...} which were not false.
#'
#' @param ...
#' Any number of (logical) R expressions,
#' which should evaluate to \code{TRUE}.
#'
#' @return
#' (\code{NULL} if all statements in \code{...} are \code{FALSE}.)
#'
#' @seealso \code{\link[base]{stopifnot}} from package \pkg{base}.
#'
#' @export
#'
#' @examples
#' \dontrun{
#' stopif(is.empty(c(2,1)), 4 < 3) # all FALSE
#' stopif(is.empty(numeric(0)))
#' }
#'
stopif <-
function(...)
{
n <- length(ll <- list(...))
if (n == 0L)
return(invisible())
mc <- match.call()
for (i in 1L:n) {
if (!(is.logical(r <- ll[[i]]) && !anyNA(r) && all(!r))) {
ch <- deparse(mc[[i + 1]], width.cutoff = 60L)
if (length(ch) > 1L)
ch <- paste(ch[1L], "....")
stop(sprintf(ngettext(length(r), "%s is TRUE", "%s are not all FALSE"),
ch),
call. = FALSE, domain = NA)
}
}
invisible()
}
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