dot-check_scalar: Check if an object is a scalar
In stbl: Stabilize Function Arguments

.check_scalar

R Documentation

Check if an object is a scalar

Checks if an object is a scalar, allowing for NULL and zero-length vectors if specified.

.check_scalar(
  x,
  allow_null = TRUE,
  allow_zero_length = TRUE,
  x_arg = caller_arg(x),
  call = caller_env(),
  x_class = object_type(x)
)

`x`	The object to check.
`allow_null`	`⁠(length-1 logical)⁠` Is NULL an acceptable value?
`allow_zero_length`	`⁠(length-1 logical)⁠` Are zero-length vectors acceptable?
`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.
`x_class`	`⁠(length-1 character)⁠` The class name of `x` to use in error messages. Use this if you remove a special class from `x` before checking its coercion, but want the error message to match the original class.