RE: [boost] program_options wchar_t support

From: Bryan Leppard (leppard_at_[hidden])
Date: 2004-02-24 15:18:18

If you are interested, I have jury-rigged program_options so that you can
switch between building it for Ansi or Unicode. Unfortunately it will
probably only work for VC 7.1 but it demonstrates one approach.

It serves my purpose for now but I don't think that this approach is
appropriate for a Boost library. However, it may be a starting point for
conversion to templates since I had to use aliases for all occurrences of
char and std::string.

Regards,
 
Bryan Leppard

 
 

-----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