Allen Cronce wrote:
fs::path inPath;
po::options_description desc("Allowed options");
desc.add_options()
("in,i", po::valuefs::path(&inPath), "Input file or directory
<pathname>")
If I call the above with the following parameters, it works:
--in "my_file"
Input path = "my_file"
But if I call it with a path that has a space in it, I get an error:
--in "my file"
Exception error: in option 'in': invalid option value 'my file'
I know that I can work around the problem by loading the path into an
interim string first, then use the string to initialize a path object.
But unless I'm missing something, I would have thought that
iteroperability between boost.program-options and boost.filesystem
should be more seamless. It seems very common to want to load options
into path objects.
I am not aware of boost.program_options has any special support for
boost::filesystem::path, which suggests that processing of this option
goes via generic path:
template
void validate(boost::any& v,
const std::vector< std::basic_string<charT> >& xs,
T*, long)
{
validators::check_first_occurrence(v);
std::basic_string<charT> s(validators::get_single_string(xs));
try {
v = any(lexical_cast<T>(s));
}
catch(const bad_lexical_cast&) {
boost::throw_exception(invalid_option_value(s));
}
}
and the error message you get is 'what()' of invalid_option_value. In other
words, it appears that lexical_cast from a string with spaces into
boost::filesystem::path does not work. And it clear why:
template< class Path >
std::basic_istream< typename Path::string_type::value_type,
typename Path::string_type::traits_type > &
operator>>
( std::basic_istream< typename Path::string_type::value_type,
typename Path::string_type::traits_type >& is, Path & ph )
{
typename Path::string_type str;
is >> str;
ph = str;
return is;
}
Extractor operator for string stops on whitespace. The fix, IMO, is
to special case conversion to boost::filesystem::path in lexical_cast,
just like it's already done for conversion to string.
Beman, what do you think?
- Volodya
