Eric Niebler schrieb:
Ok, i have understood that child nodes must share a tag type with the parent node as indicated by the document template<typename Tag, typename Fun> struct recurse_if_ : proto::if_ <http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/if_.html><; // If the current node has type type "Tag" ... boost::is_same<proto::tag_of <http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/tag_of.html><proto::_ <http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/_.html>>, Tag>(), // ... recurse, otherwise ... proto::fold <http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/fold.html><proto::_ <http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/_.html>, proto::_state <http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/_state.html>, recurse_if_<Tag, Fun> >, // ... apply the Fun transform. Fun
{}; So my next step will be to define my own fold function. Thanks a lot to all the people here. Cheers Kim Tang
My advice to you would be the same as my advice to Kim. Much can be done with recursion and proto::fold. Copy the implementation from proto::fold_tree or proto::reverse_fold_tree and modify it as needed.
http://boost-sandbox.sourceforge.net/libs/proto/doc/html/boost/proto/fold_tr...
HTH,