[boost] Re: [program_option] allow_unregistered now works

From: Vladimir Prus (ghost_at_[hidden])
Date: 2005-05-06 07:36:34

Caleb Epstein wrote:

>> Finally, the new functionality might not work nice with long options that
>> start with a single dash (allow_long_disguise style option):
>> 
>>    -foo
>> 
>> will be considered as short option '-f' with value 'oo', and never as
>> long option 'foo'.
> 
> Would this only be if "f" is a registered option, or even if it is
> unregistered?  I'd think in the unregistered case you'd end up with -f
> and two -o's as in the -cd case above.  

In the -cd case above we don't have a third letter and '-c' is registered.
For -foo case where '-f' is not registered we can treat it either as

  (-f, "oo")

or as

  (-f,)
  (-o,)
  (-o,)

I still prefer the first variant, because in this case, if some later code
knows -f, it will get the value without problems. If we split -foo into
three options without even knowing what's -f, it might be problematic to
get (-f, "oo") later.

> Whichever the case, I agree 
> that -foo should not be treated the same way as --foo.  But I grew up
> using GNU tools, so I'm biased towards the double-dash syntax.

Yea, me too.

> Overall I think this is great.  It makes it straightforward to chain
> option processing across different modules.

I think different modules scenario should be supported already. Each module
can provide its own options_description, which can be then combined into a
single options_description object used for parsing. Every module can then
use the 'variables_map' object to get its parameters.

- Volodya