Check missing formal argument

These functions check whether a value was specified as an argument to a function.

Usage

check_missing(x)

assert_missing(x)

test_missing(x)

Arguments

x

[any]
A formal argument.

Value

Depending on the function prefix:

• If the check is successful, assert_missing() returns x invisibly, whereas check_missing() and test_missing() return TRUE.

• If the check is not successful, assert_missing() throws an error message, test_missing() returns FALSE, and check_missing() returns a string with the error message.

See also

Other package helpers: Dictionary, Storage, find_namespace_calls(), identical_structure(), input_check_response(), match_arg(), package_logo(), print_data.frame(), print_matrix(), system_information(), unexpected_error(), user_confirm()

Examples

f <- function(x) {
  check_missing(x)
}
f()
#> [1] "Argument needs a value"

g <- function(x) {
  test_missing(x)
}
g()
#> [1] FALSE

h <- function(x) {
  assert_missing(x)
}
if (FALSE) { # \dontrun{
h()
} # }