[boost] [filesystem] Major changes before standardization

From: Beman Dawes (bdawes_at_[hidden])
Date: 2004-11-11 12:20:23

I'm currently working on a major revision of the Boost filesystem library 
aimed at getting it ready to be proposed to the C++ committee for the next 
Library TR.

The critical technical change required is internationalization. The plan is 
to provide a templated basic_path class, with typedefs for path and wpath. 
In other words, an approach very similar to the current std::basic_string, 
std::string, and std::wstring.

Doing this adds a certain amount of complexity compared to the current path 
class. For example, a path_traits class has to be introduced to give 
basic_paths on user defined types a way to import the conversions, 
delimiters, and other traits.

To offset the added complexity, I'd like to reduce some of the complexities 
in the current design:

* Eliminate the distinction between native and generic grammars; either 
would be permitted in all contexts. As well as simplifying the class 
interface a bit, this will also eliminate a source of user confusion.

* Move the name error checking from the basic_path class into stand alone 
functions. Although the current error checking could be further improved by 
Peter Dimov's suggested change allowing failure to be treated as either a 
warning or a hard error, moving it out of the class simplifies the 
interface, allows full path (rather than name-by-name) error checks, and 
eases internationalization.

The primary downside of these changes will be that users who want path 
portability checks will have to code calls to checking functions that are 
currently being called automatically.

The internationalization of the library is a big enough change that we will 
probably want to have at least a mini-review once the changes are complete. 

Comments?

--Beman