Converts this to a “datestruct” broken-down time structure.
A “datestruct” is a format of struct that Tablicious came up with. It is a scalar
struct with fields Year, Month, and Day, each containing
a double array the same size as the date array it represents. This format
differs from the “datestruct” used by
datetime in that it lacks
Hour, Minute, and Second components. This is done for efficiency.
The values in the returned broken-down time are those of the local time in obj’s defined time zone, if it has one.
Returns a struct with fields Year, Month, and Day. Each field contains a double array of the same size as this.