Alexei Alexandrov wrote:
Hi,
in several places I need to have code which works both with char and wchar_t. Those are template functions. I also work with paths there so I wanted to actually write something like
template <typename CharType> void foo(const std::basic_string<CharType>& s) { typedef fs::basic_path<std::basic_string<CharType> > path_type; ... }
but it turned out that I can't do it because 1) basic_path has the second Traits template parameter mandatory and 2) this Traits parameter has actually different type for path and wpath:
struct path_traits; typedef basic_path< std::string, path_traits > path; // ... struct BOOST_FILESYSTEM_DECL wpath_traits; typedef basic_path< std::wstring, wpath_traits > wpath;
Of course, I can easily workaround it with my own traits, but I wonder could it be in the first place like:
template<class String> class basic_path_traits;
template<class String, class Traits = basic_path_traits<String> > class basic_path;
with basic_path_traits being specialized for std::string and std::wstring and fs::path and fs::wpath being just
typedef basic_path< std::string > path; typedef basic_path< std::wstring > wpath;
I've created ticket #1936 with the above. There are two perspectives to consider at this issue. * As a very specific tweak to the current interface. * As a further indication that there should be a single path type that can handle both wide and narrow types. Peter Dimov suggested that once, and I keep turning over in my mind how it could be accomplished. With C++0x supplying two new character types, the need becomes more pressing. I still don't want to invent a solution that applies only to filesystem paths; there is a general need for strings that can cope with multiple character types and encodings. Thanks, --Beman