Neal Becker wrote:
I have been using boost::range heavily, and find it useful for generic interfaces. I think it is also useful to have a multi-dimensional extension to range. In particular, a 2-d extension would help in creating algorithms that can accept a variety of 2-d structures.
For example, range has size, begin, end.
range2d would have size1, size2, begin1, begin2.
Other useful members might include row, col.
Yes, I have been thinking along the same lines. In fact I thought about this earlier today after Janek Kozicki posted asking what the focus of the proposed SoC geometry library is. I would very much like to see some 2D containers, e.g. set<point2d> and map<point2d,T>, implemented using R-trees or similar. For Boost, I presume that any such code will be expected to be "standard library like", and I was wondering how similar a set<point2d> can be to a set<int>. In particular, when I want to iterate over all the points within a rectangle, I would love to be able to write: for(set<point2d>::const_iterator i = points.lower_bound(point2d(x0,y0)); i != points.upper_bound(point2d(x1,y1)); ++i) Unfortunately it can't be quite that similar to the 1D case. Currently I have some very crude code where I define what I call a "window" into the set of points: window w(points,point(x0,y0),point(x1,y1)); for(set<point2d>::const_iterator i = w.begin(); i != w.end(); ++i) Of course, having seen Neal's message, I realise that my "window" is just a 2D range. Clearly, it would be a good plan to get basics like this (and things like a point type) thought about before Huseyin Akcan starts on his SoC work. (Huseyin, I hope you're reading this! Do please let us know what exactly you intend to do.) I have been considering writing something to implement set<point> using space filling curves. I haven't thought about it much yet and would value any suggestions. My hope is that using this technique I can adapt the standard associative containers to work with 2D points, and thereby avoid having to implement any tree stuff. In my case I'm dealing with latitude/longitude values and I think that the first thing I need is a fixed-point type, so that I can do the bit interleaving that the space filling curves need. That could make a simple self-contained Boost library - is anyone interested? Phil.