Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!
Get Started for Free
rst_abort
Jump to the abort restart
Description
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()).
Usage
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()
# 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")
}
## End(Not run)
# 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")
}
## End(Not run)
# 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")
## End(Not run)