Re: [boost] [program_options] custom validator overrides

Subject: Re: [boost] [program_options] custom validator overrides
From: James E. King III (jking_at_[hidden])
Date: 2018-10-16 00:30:52

On Mon, Oct 15, 2018 at 7:16 PM Roger Martin via Boost <
boost_at_[hidden]> wrote:

> Hi,
>
> The Custom Validators documentation
> https://www.boost.org/doc/libs/1_68_0/doc/html/program_options/howto.html
> shows
>
> void validate(boost::any& v,
>                const std::vector<std::string>& values,
>                magic_number* target_type, int)
> {
>
> but the possible templates don't match; the last variable type is an
> int; the key is matching this last type:
>
> int goes with std::vector<T>*
>
> long goes with T*
>
> it also seems possible to hit the
>
>      void validate(boost::any& v,
>                    const std::vector<std::basic_string<charT> >& s,
>                    boost::optional<T>*,
>                    int)
>      {
>
> where it then calls for get_single_string and if you are trying for a
> multitokens switch args, it'll throw " only takes a single argument".
>
> which also varies if it was parsed by command_line_parser or
> parse_config_file
>
> command_line_parser: vector size can >= 1 up to number of switch args
>
> parse_config_file: vector size ==1 no matter what the number of args are
> on the input.  just one string with all switch args.
>
> This was tested with 1.65 yet I don't see anything changing in
>
> https://github.com/boostorg/program_options/blob/develop/include/boost/program_options/detail/value_semantic.hpp
>
>
Please submit a pull request or open a github issue to track this properly.

Thanks,

Jim