An implementation of bounded obligations

An implementation of bounded obligations is demonstrated. Bounded obligations facilitate the expression of requirements such as `a user must return a book on or before its due date´. The implementation translates a simple, declarative form of a bounded obligation into the equivalent data structures and operations necessary to ensure its adherence. Incremental development and exploration is achieved by modifying a `strict´ bounded obligation to become `violatable´ together with a way of recognizing when it has been violated. Again, a simple declaration to this effect is appropriately translated by the implementation. Finally, response to such violations can also be declared and automatically translated into running code. The implementation is described and illustrated on examples drawn from a simple library system