Re: [boost] gregorian date - default constructor & more.

From: Pavol Droba (droba_at_[hidden])
Date: 2004-01-12 01:43:19

On Sun, Jan 11, 2004 at 07:01:09PM -0700, Jeff Garland wrote:
> On Sun, 11 Jan 2004 21:22:06 +0100, Pavol Droba wrote
> > Hi,
> > 
> > Is there any reason, why there is no default constructor provided 
> > for date classes in the date_time library? 
> >
> >I seems to me, that it 
> > would be quite reasonable to provide it, while intializing the 
> > object to not_a_date_time. Current implementatio seems to be 
> > unreasonably restrictive.
> 
> The reason is because I don't really like default constructors. Perhaps
> surprisingly this is only the second time I recall this coming up.  Last time
> it seems that I was pretty much convinced, but it never happened.
> 
> http://aspn.activestate.com/ASPN/Mail/Message/boost/1508692

In my application, I need the default constructor. I'm using a templated code,
and I'm using default-constuctible values as defaults, when no other value
can be computed. Because it is a generic code, I have no way to find out 
what a value to use to initialize a particular type. (well, I can factor out 
the initialization to some function and overload it for all the different types, 
but it would simply do the same thing as the default constuctor, so I don't 
consider this as a reasonable solution).

> Of course you can do it by changing one line of code:
> 
> Change boost/date_time/gregorian/greg_date.hpp::68
>    explicit date(special_values sv):
> to
>    explicit date(special_values sv = not_a_date_time):

This is exactly what I did, to solve my problem. I'm just wondering why it is not
official. 

> 
>  
> > The other issue is, if there is a plan to add unicode support to the 
> > library.
> 
> Can you be a bit more specific about what you want?  The streaming code should
> already support unicode if the underlying stream supports it.  

I had to_xxx_string and from_xxx_string functions in mind. I would like to have wstring
variants, so I don't have to convert the string from unicode and back each time I'm using them.

Regards,

Pavol.