I'll make a start:

• Implementation of std::function and std::bind. This could be similar to the talk on std::shared_ptr.
• Concurrency-related: <thread>, <future>, <async>.
• I think STL mentioned that VS11 would have new features pertaining to allocator support; if that's mature already, that could be worth talking about.

What do you think? Any favourite topics that come to mind?

By the way, you were missing the last template parameter in the operator with the print_container_helper argument. I'll update my modified code (and add an example of custom delimiters), but I wanted to let you know.

I'd also like to use some template aliases for char- and wchar_t delimiter classes a la "template<typename T> using sdelims = delimiters<T, char>. Shame my GCC4.4 doesn't seem to understand.

Finally, I want to get a generic outputter for std::tuple, too, like we have for pair; now trying to work through variadic templates...

Edit: I just added a C array wrapper, check out my updated code on SO!

The only problem I can see is if you try to directly stream-out an object of a class for which you haven't defined an operator and which have iterators -- if you did have an overloaded operator, it would take precedence, and if you didn't and don't want it to be used like this, then you shouldn't write "cout << x". So... I really can't think of a way in which our templates would break an existing program. Please do tell if you have an example!

Edit:

Bonus question: Can we SFINAE between "*iterator == pair<K,V>" and "*iterator == T"?

Edit: I see your point about the string class, but wouldn't the string's operator<< be more specialized?

One thing, though: Can we add associative container support to print a map like "{1: hello, 2: world, 3: foobar}"? Oh, I see that it works for maps, but not for unordered_maps. Does the code require explicit predeclaration of all supported container types? Perhaps that could be wrapped into a macro for the client code...

Maybe we can use SFINAE to determined automagically whether a class supports ::begin() and ::end()?!

Edit: I think I have made a trait class to detect the presence of iterators!

template<typename T>
struct mycont_helper
{
private:
  template<typename C> static char test(typename C::iterator*);
  template<typename C> static int  test(...);
public:
  static const bool __value = sizeof(test<T>(0)) == sizeof(char);
};

template<typename T>
struct mycont : public std::integral_constant<bool, mycont_helper<T>::__value>
{ };

Usage: mycont&lt;T&gt;::value will be true for containers and false otherwise.

Task: Write a templated solution that will pretty-print the contents of any STL container, or more generally anything that supports begin/end iterators.

I originally posted this question on StackOverflow (http://stackoverflow.com/questions/4850473/pretty-print-c-stl-containers), but looking back at it I'm still not happy with any of the proposed solutions.

Synopsis: Given something like std::CONTAINER x, I want to write "std::cout << x;" and get something like "{1, 5, -3, 12}" (with customizable delimiters), but I don't want to have to change the code to accomodate new containers -- I'd like a single piece of code that will work for ALL containers that have begin/end.

Any suggestions (also to the original SO page) would be most welcome!