CLP(H) is an instantiation of the general constraint logic programming scheme with the constraint domain of hedges. Hedges are finite sequences of unranked terms, built over variadic function symbols and three kinds of variables: for terms, for hedges, and for function symbols. Constraints involve equations between unranked terms and atoms for regular hedge language membership. We study algebraic semantics of CLP(H) programs, define a sound, terminating, and incomplete constraint solver, investigate two fragments of constraints for which the solver returns a complete set of solutions, and describe classes of programs that generate such constraints.

In current commercial feature modeling systems, support for direct manipulation of features is not commonly available. This is partly due to the strong reliance of such systems on constraints, but also to the lack of speed of current constraint solvers. In this paper, an approach to the optimization of geometric constraint solving for direct manipulation of feature dimensions, orientation, and position is described. Details are provided on how this approach was successfully implemented in the Spiff feature modeling system.

This article contains a description of a constraint solver that determines complete solution spaces. These spaces are defined by sets of constraints in continuous variables. Interactive design is supported through improvements to existing algorithms that have increased system performance. In addition, heuristics for activating the best set of preferred constraints for a design task are presented, and two ways are proposed for interactively exploring design alternatives. IDIOM is an application framework that has successfully tested these algorithms for interactive apartment layout design.