Throws an error if x is missing.

## Usage

check_required(x, arg = caller_arg(x), call = caller_env())

## Arguments

x

A function argument. Must be a symbol.

arg

An argument name as a string. This argument will be mentioned in error messages as the input that is at the origin of a problem.

call

The execution environment of a currently running function, e.g. caller_env(). The function will be mentioned in error messages as the source of the error. See the call argument of abort() for more information.

arg_match()

## Examples

f <- function(x)  {
check_required(x)
}

# Fails because x is not supplied
try(f())
#> Error in f() : x is absent but must be supplied.

# Succeeds
f(NULL)