on Mon Oct 29 2012, Mathias Gaunard <mathias.gaunard-AT-ens-lyon.org> wrote:
On 29/10/12 22:33, Dave Abrahams wrote:
on Mon Oct 29 2012, Mathias Gaunard <mathias.gaunard-AT-ens-lyon.org> wrote:
On 29/10/12 20:29, Dave Abrahams wrote:
Using recursive_variant_ works out quite nicely, except that it doesn't allow me to separately declare "object" and "array" and re-use them in the definition of "value":
typedef boost::make_recursive_variant< null , std::string , double , std::map<std::string, boost::recursive_variant_> , std::vector<boost::recursive_variant_> , bool >::type value;
I'd use this method, it's clearly the cleanest. I don't understand what's your problem with it.
As I had feared, and as http://news.gmane.org/find-root.php?message_id=%3cm2objlggaw.fsf%40pluto.lua... demonstrates, extra dynamic allocations will be used to store maps and vectors (or anything at all?) in the variant.
I should also point out that it might be putting the indirection in the "wrong" place. having the recursive_wrapper around the whole map or vector is clearly more efficient than having it around (part of) their elements.
Why not fix the implementation then instead of writing hacks?
I realized it's not completely fixable as Steven points out. I actually did think of trying to do something about other issues, https://svn.boost.org/trac/boost/ticket/7601, but...
Of course, the code of variant is horrible enough to make it very difficult to do anything with it.
...exactly. -- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost