Doug Gregor wrote:
A while ago I announced the availability of an implementation of "variadic templates" for GCC. Variadic templates eliminate a huge amount of redundancy in several Boost libraries (including some that have gone into TR1), such as tuples, function, bind, mem_fn, and MPL. I have now completed the compiler (everything I've thought to try works) and completely reimplemented TR1's <tuple> and <functional> headers using variadic templates. The resulting code is much smaller, clean, and compiles significantly faster that the previous versions. Compiler binaries and sources, both including the implementation of TR1, are available here:
http://www.osl.iu.edu/~dgregor/cpp/variadic-templates.html
I think variadic templates are a big step forward for C++ libraries that deal with function objects, forwarding, and type-lists. If you're interested, please read the documentation, hack some code with the compiler, and tell your local C++ committee representative to vote for variadic templates in C++0x :)
FWIW, I'll add a quick word of support for this feature. I ran into this very issue with my implementation of the 'super_string' class where I wanted to have an unlimited number of template function parameters for functions like type conversion and and formatted output. It's painful to write/test all the different overloadings to an 'arbitrary level'. Honestly, I punted and didn't write as many overloads as I should have...luckily no one has complained - yet ;-) I looked at your spec when you first posted and I believe it would solve my issue quite nicely. Thanks for doing this. Jeff