Questioning lifecycle

The abort restart is the only restart that is established at top level. It is used by R as a top-level target, most notably when an error is issued (see abort()) that no handler is able to deal with (see with_handlers()).

rst_abort()

Life cycle

All the restart functions are in the questioning stage. It is not clear yet whether we want to recommend restarts as a style of programming in R.

See also

Examples

# The `abort` restart is a bit special in that it is always # registered in a R session. You will always find it on the restart # stack because it is established at top level: rst_list()
#> [[1]] #> <restart: abort > #>
# You can use the `above` restart to jump to top level without # signalling an error:
# NOT RUN { fn <- function() { cat("aborting...\n") rst_abort() cat("This is never called\n") } { fn() cat("This is never called\n") } # }
# The `above` restart is the target that R uses to jump to top # level when critical errors are signalled:
# NOT RUN { { abort("error") cat("This is never called\n") } # }
# If another `abort` restart is specified, errors are signalled as # usual but then control flow resumes with from the new restart:
# NOT RUN { out <- NULL { out <- with_restarts(abort("error"), abort = function() "restart!") cat("This is called\n") } cat("`out` has now become:", out, "\n") # }