dot-to_null: Ensure an argument is NULL
In stbl: Stabilize Function Arguments

.to_null

R Documentation

Ensure an argument is NULL

If allow_null is TRUE, coerce x to NULL. Otherwise throw an informative error.

.to_null(x, allow_null = TRUE, x_arg = caller_arg(x), call = caller_env())

`x`	The argument to stabilize.
`allow_null`	`⁠(length-1 logical)⁠` Is NULL an acceptable value?
`x_arg`	`⁠(length-1 character)⁠` An argument name for x. The automatic value will work in most cases, or pass it through from higher-level functions to make error messages clearer in unexported functions.
`call`	`(environment)` The execution environment to mention as the source of error messages.