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Print a warning or message only once

Source: R/messages.R
onetime_warning.Rd

These functions use onetime_do() to print a warning or message just once.

Usage

onetime_warning(
  ...,
  id = deprecate_calling_package(),
  path = default_lockfile_dir(),
  expiry = NULL,
  without_permission = "warn"
)

onetime_message(
  ...,
  id = deprecate_calling_package(),
  path = default_lockfile_dir(),
  expiry = NULL,
  without_permission = "warn"
)

onetime_startup_message(
  ...,
  id = deprecate_calling_package(),
  path = default_lockfile_dir(),
  expiry = NULL,
  without_permission = "warn"
)

Arguments

...

Passed to warning(), message() or packageStartupMessage().

id

Unique ID string. If this is unset, the name of the calling package will be used. Since onetime 0.2.0, not setting id is deprecated.

path

Directory to store lockfiles. The default uses a unique directory corresponding to the calling package, beneath rappdirs::user_config_dir(). Normally you should leave this as the default.

expiry

difftime() or e.g. lubridate::duration() object. After this length of time, code will be run again.

without_permission

Character string. What to do if the user hasn't given permission to store files? "warn" runs the action with an extra warning; "run" runs the action with no warning; "pass" does nothing and returns the default; "stop" throws an error; "ask" asks for permission using check_ok_to_store(), and returns the default if it is not granted.

Value

Invisible TRUE if the message/warning was shown, invisible FALSE otherwise.

See also

onetime_do()

Examples

oo <- options(onetime.dir = tempdir(check = TRUE))
id <- sample(10000L, 1)

for (n in 1:3) {
  onetime_warning("will be shown once", id = id)
}
#> Warning: will be shown once

onetime_reset(id = id)
options(oo)