Re: [Boost-users] [date time] are months and years derived from date_duration?

From: Jeff Garland (jeff_at_[hidden])
Date: 2007-05-27 17:08:26

On Sun, 27 May 2007 21:06:09 +0200, Seweryn Habdank-Wojewódzki wrote
 
> So to summarize I know one exact date (clicked one), and I want to 
> generate others. Below is small example:
> 
>     bg::date const final_date(2020,12,31);
>     bg::months const every_month(1); // this TYPE is variable in runtime
>     bg::date d0(2007,3,4);  
>     do
>     {
>         d0 += every_month;
>         cout << d0 << '\n';
>     }
>     while (d0 < final_date);
> 
> I am trying to use boost::variant for that purpose.

Ok, I would suggest you take a look at the date_iterator -- I think this will
provide the framework you need.  The library provides basically 4 variations
on the date_iterator - month_iterator, year_iterator, week_iterator, and
day_iterator.  These take a date as a starting point and will then calculate
the next increment.  so you can change your code to something like:
     month_iterator itr(date(2007,3,4));

     //the following code is generic and would work with a date, week,
     //month, or year iterator.
     do
     {
         itr++;
         cout << *itr << '\n';
     }
     while (itr < final_date);

It turns out that you can use the base type
date_itr_base<boost::gregorian::date> to virtually dispatch.  You can also
replace the functor in the iterators to create your own logic if you want. 
You can look at the examples/test and source for more details.

Jeff