RE: [boost] program_options wchar_t support

From: Bryan Leppard (leppard_at_[hidden])
Date: 2004-02-17 13:27:45

I don't know how important conversions are to other people. When I write a
Unicode program it is pure. I expect to use all Unicode characters, strings,
and literals. I expect that I will have to handle any required conversions
outside the library. 

I agree with the suggestion to set it up with just the specializations for
char and wchar_t similar to std::string and std::wstring. 

Regards,

Bryan Leppard
Neotechnology Consultants Ltd.

-----Original Message-----
From: Vladimir Prus [mailto:ghost_at_[hidden]] 
Sent: February 14, 2004 9:29 AM
To: Boost mailing list; Bryan Leppard
Subject: Re: [boost] program_options wchar_t support

Hi Bryan,
> Any plans on adding support for parsing wchar_t in the program_options
lib?
> It is hard coded with std::string right now which makes it kind of useless
> in a program where argv is a wchar_t**.

The review manager indicated that unicode (~= whar_t) support is needed for 
the final version of library, so yes, there are such plans. The problem is 
that it's probably the only planned change for which I haven't yet decided 
the design.

> It could be templatized so that it can be based on any kind of
> std::basic_string.

Alas, that would break ability to put all sources in a library -- thereby 
increasing compile time for users who don't need wchar_t support.

> Alternatively, you could use preprocessor defines to control whether it
> builds for ANSI or UNICODE. This would probably be adequate for its
> intended use as well as less complicated to implement but I suspect it
> would not be portable enough for BOOST.

That's an option too. Could you answer a couple a questions to help me with 
design:

1. Do you need wchar_t for option values, or for option names too?

2. Do you plan to mix char and wchar_t? If so, how 'char' is to be converted

to wchar_t? What if I require to provide a converting function for that
case?

3. If you plan to use wchar_t for option names, how will use specify names
in 
code? Using unicode literals or using some specific 8-bit encoding? If the 
latter, how convertion to unicode is to be done? Again, is user-provided 
converter okay for you?

Thanks,
Volodya