Represents a period of time with respect to a notional point in time, which is not
specified. A sign may be used to indicate the duration is backwards in time
rather than forwards.
NOTE: a deviation from ISO8601 is supported, allowing the W' designator to
be mixed with other designators. See assumed types section in the Support IM.
Used for recording the duration of something in the real world, particularly when
there is a need a) to represent the duration in customary format, i.e. days, hours,
minutes etc, and b) if it will be used in computational operations with date/time
quantities, i.e. additions, subtractions etc.
Durations cannot be used to represent points in time, or intervals of time.
Declaration :
Artifact : DV_DURATION
All public operations : is_normal , is_simple , is_strictly_comparable_to , operator+ , operator- , operator< , operator= , valid_magnitude_status , valid_percentage