Check if an argument is single TRUE or FALSE. As an option it is
possible to allow NULL
value when alt_null = TRUE
.
check_bool(x, alt_null = FALSE, add_msg = NULL)
If argument is single TRUE
or FALSE
(optionally NULL
) it
returns invisible NULL
. Otherwise the function throws an error.
Function argument that is being asserted.
Logical. Should argument accept NULL
value.
Is an additional message that can be printed over the standard function error message. You can:
pass the names of the arguments that failed the test by using
{x_name}
in the message body (e.g. "What are the {x_name}");
pass the class of the arguments that failed the test by using
{wrong_class}
in the message body (e.g. "{wrong_class} is wrong")