RE: [Boost-Users] Unelegant constructs in date_time

From: Jeff Garland (jeff_at_[hidden])
Date: 2003-06-27 09:23:49

> Here's a list of a few things I find unelegant in the date_time
> package:
> 
> 1. Order or parameters
> 
>    Consider these declarations:
> 
>         date d(year, month, day);
>         partial_date pd(day, month);
> 
>    So date() uses month before day, while partial_date() uses day
>    before month.

Yes, this was recently changed.  The reason is that partial_date is a date generator
like 'first_kday_after' (eg: 'First Monday in January') and I was able to write 
time adjustment code more cleanly by keeping he month as the second parameter in 
all date generators.
 
> 2. No += and -=
> 
>    I can say
>         date1 = date1 + date_duration(3);
>    but not
>         date1 += date_duration(3);

Good point.  Apparently we aren't using boost::operators aggressively enough
here.  I'll put it on the todo list.

> 3. Namespace problems
> 
>    Date generators are in different namespaces: Both partial_date and
>    first_kday_of_month are found in boost::date_time, but partial_date
>    is also carried over in boost::gregorian, whereas
>    first_kday_of_month is not.

Fixed in CVS. All the generators are now available in boost::gregorian.

> 4. Inconsistent abbreviations
> 
>    If I want the first Thursday in September, I must write:
> 
>      boost::date_time::first_kday_of_month<date> fts(Thursday, Sep); 
> 
>    'Thursday' must not be abbreviated to 'Thu'.
>    'Sep' must not be unabbreviated to 'September'.

True.  If you really need this you can just update boost/date_time/date_defs.hpp
to the way you want it.

> 5. Misleading exception string
> 
>    This code:
>         try {
>             date d(2003, Feb, 29);
> 	}
> 	catch (std::out_of_range exc) {
> 	    std::cout << "Caught exception: " 
>         	      << exc.what() << std::endl;
> 	}
> 
>    surprisingly outputs this text:
> 
>        Caught exception: Day of month value is out of range 1..31
> 
>    So, it seems that 29 is not in the range 1..31.

Fixed in CVS.  Now you will get "Day of month is not valid for year"
instead.

Jeff