validate_args: Check the values of function arguments

In healthiar: Quantifying and Monetizing Health Impacts Attributable to Exposure

Check the values of function arguments

Description

Low-level helper used by the data validation of the healthiar functions (e.g. validate_input_attribute(), socialize(), monetize()).

It takes the list of argument values, the names of the arguments to be checked and a predicate returning TRUE for the valid values. Arguments that are NULL (i.e. not entered by the user) are skipped, so the callers do not have to filter them beforehand.

Usage

validate_args(
  args,
  arg_names,
  is_valid,
  message,
  report = "first",
  type = "error"
)

Arguments

args	List with the argument values, i.e. input_args$value.
arg_names	Character vector with the names of the arguments to be checked. Names that are not in args are ignored.
is_valid	Function taking the argument value and returning TRUE for the valid values. It can be vectorized; the argument is invalid if any of its values is not valid.
message	String with the message. Write {arg} where the name(s) of the argument(s) concerned have to appear.
report	String specifying which arguments are named in the message. Options: "first" (default, only the first argument found to be invalid), "all" (all invalid arguments, separated by commas).
type	String specifying the condition to be signalled. Options: "error" (default), "warning".

Details

report

Use "first" when the message is specific to one argument (e.g. the options of a categorical argument), so that the users are not confronted with the options of all arguments at once. Use "all" when the message is the same for all arguments (e.g. "must not be lower than 0"), so that the users can correct all of them in one go instead of one at a time.

Order of the calls

The order of the calls matters: a predicate is only safe once the previous calls have ruled out the value types it cannot handle. E.g. checking whether a value is a whole number (x == floor(x)) requires that the numeric check has already been passed.

Value

This function returns nothing. It is called for its side effect, i.e. an error or a warning if any of the argument values is not valid.

Author(s)

Alberto Castro & Axel Luyten

Examples

## Not run: 
# Message about one single argument
validate_args(
  args = input_args$value,
  arg_names = c("n_quantile", "population"),
  is_valid = is.numeric,
  message = "{arg} must contain numeric value(s).")

# Message listing all the arguments concerned
validate_args(
  args = input_args$value,
  arg_names = c("prop_pop_exp", "dw_central"),
  is_valid = function(x){x <= 1},
  message = "The values in the following arguments must not be higher than 1: {arg}.",
  report = "all")

## End(Not run)

healthiar documentation built on Oct. 12, 2026, 5:07 p.m.