Function builtin_typeof 

fn builtin_typeof(
    args: &[RValue],
    _: &[(String, RValue)],
) -> Result<RValue, RError>

Get the internal type of an object.

Returns the low-level type name (e.g., “double”, “integer”, “character”, “logical”, “list”, “closure”, “builtin”, “NULL”).

@param x object to inspect @return character scalar