Hello, in http://permalink.gmane.org/gmane.comp.lib.boost.devel/207794 Robert Ramey talked about wrapping some POD to increase type safety. Some time ago I used something similar to ensure that misuse of values can be found by the compiler. So I think that is something that can be generalized. The concept is to wrap a type into a class and restrict the interface. This ensures that values from one context (e.g. an id) can't be used in another context (e.g. adding of number or as an id for other objects). Attached is a very simple implementation where the needed concepts can be specified as parameter. To distinguish for example between different id types also a tag type can be specified. Do you think this might be a useful utility? Or is there something similar already available? I've searched the vault but did not find anything. Regards Henning