R/on_error.R

In ColinFay/attempt: Tools for Defensive Programming

#' Add a function to be run on error
#'
#' This function behaves as `on.exit()`, but is run on error, and supports mappers.
#'
#' @param f a function to call on error
#'
#' @return A local error handler.
#' @export
#'
#' @examples
#'
#' y <- function(num) {
#'   on_error(~ write(Sys.time(), "error_log.txt", append = TRUE))
#'   log(num)
#' }
#'
on_error <- function(f) {
  f <- rlang::as_function(f)

  old <- do.call(options, as.list(c("error" = f)))

  do.call(
    options,
    list("error" = f),
    envir = parent.frame()
  )

  do.call(
    on.exit,
    list(
      substitute(options(old)),
      add = TRUE
    ),
    envir = parent.frame()
  )
}