First, I'd like to congratulate Matias and by proxy Joaquín for their work on this library -- I think it should be accepted into boost. I've used similar constructs in several real-world projects and have used my own variant of the 'recommended bi-map' wrapper from the MI library examples. This new wrapper is better. First some detailed comments/questions: 1) Tutorial docs are wrong -- namespace should be boost::bimap not 'bimap' 2) I'd suggest that we should have a top level boost header -- boost/bimap.hpp the simply includes the bimap/bimap.hpp. Not all libs have these top level headers, but most do. It's handy to just do '#include "boost/<libname>.hpp"' 3) Why not discuss bimap in terms of value_type? Here's the example from the tutorial: typedef bimap<std::string,int> results_bimap; typedef results_bimap::relation position; results_bimap results; Now normally when dealing with std::map I'd do something like this typedef std::map<std::string, int> regular_map; typedef regular_map::value_type val_type; regular_map rm; rm.insert(val_type("foo", 1)); Turns out the same thing works for bimap -- which is good :-) typedef results_bimap::value_type bm_val_type; results_bimap rbm; rbm.insert(bm_val_type("foo", 1)); So, I would suggest that the first example should leverage this similarity instead of introduce the set<relation> stuff. 4) more tutorial -- const_iterators Since the example doesn't modify the returned objects const_iterator's might be more appropriate. Luckily, just as expected the following were available: results_bimap::right_const_iterator i = rbm.right.begin(); results_bimap::left_const_iterator i = rbm.left.begin(); 5) Please add something to the tutorial to show the behavior of trying to insert when a key is already in the map: //like std::map if one of the keys is duplicated insert fails results.insert( position("Somewhere" ,4) ); //no effect! results.insert( position("France" ,5) ); //no effect! 6) More on std::map compatibility. Ok, here's what I'm wondering. For a simple bimap if I access it like an std::map shouldn't I just see the bimap.left? That is, I'd like to be able to seamlessly use bimap in place of std::map and have the 'left view' work pretty much like a std::map where feasible. Here's where this would come up. I have a little algorithm I use to simplify map coding called 'exists'. This simplifies the usual code need to find a particular key in a collection, check against the end, and then do something. Here's what it looks like: template<class CollectionType> inline bool exists(const CollectionType& c, const typename CollectionType::key_type& key, typename CollectionType::const_iterator& outItr) { typename CollectionType::const_iterator itr = c.find(key); if (itr != c.end()) { outItr = itr; return true; } return false; } And it's used like this: regular_map rm; regular_map::const_iterator rmci; if (exists(rm, "foo", rmci)) { std::cout << rmci->second << std::endl; } else { //do something else Of course if I try this with bimap it fails because key_type doesn't exist among other things. Luckily, this works: results_bimap rbm; results_bimap::left_iterator bmci; if (exists(rbm.left, "bar", bmci)) { std::cout << "exists test left:" << bmci->second << std::endl; } So, my question is, why should the bimap give me a me the .left for the standard map methods? 7) More tutorial/example docs please!! As beautiful as the docs are, I'm like alot of programmers hate reading docs. What I want to find is an example of the code I'm trying to write so I can cut it from the docs drop it into my code and start modifying. Then if I hit a roadblock I'll go back to the docs. By the time I go back to the docs I'll already have a 'feel' for the lib. Bottom line is that there needs to be lots of examples -- there aren't enough examples in the docs. 8) I'm confused about the model when bi-map uses a 'multi-set' or 'unordered-multiset'. Do these allow duplicated keys for that side? Why no bi-multimap? Overall I'm inclined to suggest that some of these features should be removed from the library for now. The examples and tests seem to be lacking (just typedefs that don't test anything AFAICT). 9) Should it be bi-collections instead of bi-map? There's a ton of other features in the library that allow for creation of different bi-directional relations. In fact, this probably constitutes the bulk of the library. Thus, I'm wondering if the library should be renamed to account for these or they should be removed and the library stripped down to the bimap essence? ****************** Some standard question responses... What is your evaluation of the design? --> Good -- it's built on top of an already solid Boost library. What is your evaluation of the implementation? --> Didn't look long enough to comment. What is your evaluation of the documentation? --> It's very complete with reference docs -- a few missing elements: 1) compiler notes (discusses any special rules/issues for various compilers), 2) design decisions -- documents any important tradeoffs and issues, 3) change log -- after it's accepted this will record bug fixes, etc. What is your evaluation of the potential usefulness of the library? --> Quite useful. Did you try to use the library? With what compiler? Did you have any problems? --> Yes, g++-4.0 on ubuntu 64 bit Linux. How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? --> 3 hours now -- looked at preliminary versions of the library in the past. I read thru the docs and compiled some examples to test out that the library works as I would expect. Are you knowledgeable about the problem domain? --> Yes Jeff