Marcin Kalicinski wrote:
My vote on the current property_tree submission is NO. I think it could be re-submitted in the future given a clear rationale accurately stating: - it's intended use - a comparison with similar libraries (have you looked at McObject's ExtremeDb as one example) - why/why not it's not based on boost.graph libray as a Directed-Acyclic-Graph
I believe this rather belongs to a domain of implementation details. What difference would there be for the users? I have a clear vision of ptree, and this is std container + extra member functions to make access a snap. I would not like to expose any boost.graph interface anyway.
My point is that these reasons should have been stated in the rationale section of the documentation. What if I'd like to use BGL's bfs or dfs on the tree? Sounds like useful functionality to me, without reinventing the wheel.
- why would I not just use map< vector<string>, data > along with upper/lower bound
Hmm. I think I have an answer below:
#include <map> #include <string> #include <vector> #include <sstream>
// I want to extract an int from some config file int i;
// That's what I've got to do:
typedef std::map< std::vector<std::string>, std::string > Container; Container container; read_xml(..., container); // Note this must be defined somewhere anyway std::vector<std::string> path; path.push_back("some"); path.push_back("arbitrarily"); path.push_back("long"); path.push_back("path"); Container::const_iterator it = container.find(path); // A very inefficient lookup if (it != container.end()) { std::ostringstream out_stream; out_stream << it->second; std::istringstream in_stream(out_stream.str()); in_stream >> i; // Finally got it! } else throw ...
Not a pretty sight, is it? I'd rather download TinyXML. Note that it already assumes there are parsers implemented somewhere else, which create that monstrous map. The map solution also does not let you manipulate the hierarchy in memory - map is a linear structure even though it is internally implemented as a tree.
Again these issues should have been stated in the rationale section. And if the above used(the current CVS version) of boost::filesystem::path and/or the boost::assign, many of your objections could be alleviated. Which also brings up a possible solution using boost::spirit::symbol, which would have the benefits of a ternarys state tree.
I believe any attempt to make the above shorter and more manageable leads just towards implementing another version of property_tree.
With a different set of abilities/limitations that the reviewers could compare. Jeff Flinn