  Object oriented constraint programs (OOCPs) emerge as a leading evolution of
constraint programming and artificial intelligence, first applied to a range of
industrial applications called configuration problems. The rich variety of
technical approaches to solving configuration problems (CLP(FD), CC(FD), DCSP,
Terminological systems, constraint programs with set variables ...) is a source
of difficulty. No universally accepted formal language exists for communicating
about OOCPs, which makes the comparison of systems difficult. We present here a
Z based specification of OOCPs which avoids the falltrap of hidden object
semantics. The object system is part of the specification, and captures all of
the most advanced notions from the object oriented modeling standard UML. The
paper illustrates these issues and the conciseness and precision of Z by the
specification of a working OOCP that solves an historical AI problem : parsing
a context free grammar. Being written in Z, an OOCP specification also supports
formal proofs. The whole builds the foundation of an adaptative and evolving
framework for communicating about constrained object models and programs.
