On Wed, 26 Apr 2006 22:21:44 +0200, Robert Kawulak wrote:
Hi,
From: Spencer Collyer
bounds: This determines what the bounds on the sparse_array are, and how values that exceed them are handled. For example, the 'unbounded' policy allows virtually any positive value of the subscript type to be used, 'bounded' only allows values within the (compile-time specified) max value and throws if a subscript exceeding this is given, while 'clamped' makes such value equal to the max value.
I'm working (actually, I'm having a long pause with the work :P) on a Boost library that will actually implement this piece of functionality, i.e. constrained types. In short, it aims to provide a set of flexible, policy-based template classes allowing to create constrained types, like bounded types with compile-type bounds, run-time specified bounds etc. The code is almost ready, but the documentation and tests need work.
If you'd be interested in reusing my library in your project, just let me know. Unfortunately I can't tell when the library would be 100% ready, although I try to finish it as soon as possible.
Below is an excerpt from the motivation section of the documentation.
Robert, Yep, I've seen some of the discussions on your Constrained Types library - probably the only thing I miss from my days being forced to program in Pascal many years ago :-) I'd love to see this library make it into Boost. The way my sparse_array class is designed there should in principle be nothing to stop a user using one of your constrained types as a subscript. However, I do have one concern - the way the iterators are handled, I need to be able to specify a value that is one-past the maximum allowed subscript (which is why the 'unbounded' policy doesn't allow to use _all_ positive values - it has to reserve the maximum value for its end() iterator). If I read your suggestion right, you are thinking that we could replace the bounds policy with one of your constrained types? Because of the need to reserve the one-past-the-end value for the end() iterator, I'm not sure that would be feasible. We need to be able to store the one-past-the-end value but not allow the user to specify it as a valid subscript. Does that make sense? I'm beginning to think I need to get something posted on the web so people have something concrete to look at... Spencer -- <<< Eagles may soar, but weasels don't get sucked into jet engines >>> 8:53am up 39 days 20:26, 21 users, load average: 0.15, 0.04, 0.02 Registered Linux User #232457 | LFS ID 11703