Re: [pdf-devel] Re: Calendar spans

[Aleksander Morgado]

>    Have you considered doing a survey of other Date/Time/Calendar
>    implementations to find out how they solve this problem? For example, a
>    lot of careful thought and research has gone into the Perl DateTime
>    modules.
>
>    
> http://search.cpan.org/dist/DateTime/lib/DateTime.pm#Adding_a_Duration_to_a_Datetime
>
> Very interesting. Thanks for the hint! :)

Yes, nice!

> It seems that the perl modules uses the same approach I was
> suggesting:
>
>    "DateTime.pm always adds (or subtracts) days, then months, minutes,
>    and then seconds and nanoseconds. If there are any boundary
>    overflows, these are normalized at each step. For the days and
>    months (the calendar) the local (not UTC) values are used. For
>    minutes and seconds, the local values are used. This generally just
>    works.
>
>    This means that adding one month and one day to February 28, 2003
>    will produce the date April 1, 2003, not March 29, 2003."

Ok, so let's follow this approach. I will explain it in detail in the 
API reference.