[boost] Re: Re: Any interest in a boost::glob() function?

From: Angus Leeming (angus.leeming_at_[hidden])
Date: 2004-10-02 07:57:16

Rob Stewart wrote:
>> This is, in essence, what I am proposing. I have now reworked the
>> interface following Gennadiy's suggestion. Here's a glob_iterator that
>> can recurse down directories:
>> 
>> class BOOST_GLOB_DECL glob_iterator
>>     : public iterator_facade<
>>                  glob_iterator             // Derived type
>>                , filesystem::path const    // value_type
>>                , single_pass_traversal_tag
>>              >
>> {
>> public:
>>     glob_iterator() {}
>>     glob_iterator(std::string const & pattern,
>>                   filesystem::path const & wd,
>>                   glob_flags flags);
>> private:
>>     ...
>> };
> 
> I think you misunderstood what Gennadiy meant.  (If not, I think
> this is a good idea, anyway.)  Your function should accept an
> output iterator through which you save the results.  That enables
> the caller to decide where the results go instead of you deciding
> that they go into a list which then must be iterated.  Thus, I'm
> proposing something like this:
> 
> template <typename OutIt, typename Char>
> OutIt
> glob(OutIt & out, std::basic_string<Char> const & pattern,
>    filesystem::path const & pathname, glob_flags flags);
> 
> Appropriate output iterators can forward the matches to a
> collection, to a GUI control, to a file, etc.

No need to parameterize on Char type. This thing uses filesystem to do the
iteration over the contents of a directory and filesystem knows nothing of
wide strings. We can/should revisit that later as and when filesystem is
changed.

As for the output iterator idea, I don't see how to use it. For example,
with my suggestion I could populate an STL container with:

        namespace fs = filesystem;
        std::list<fs::path> const matches(
            glob_iterator("*.cpp", fs::path("."), glob_brace),
            glob_iterator());

How do I do that with your idea? Once you've explained it, can you tell me
why it's better than glob_iterator, above?

Angus (ever ignorant)