Summary: The new generic scheme CFLP\((\mathcal D)\) has been recently proposed in [F. J. López-Fraguas, M. Rodríguez-Artalejo and R. del Vado Vírseda, “Constraint functional logic programming revisited”, Electron. Notes Theor. Comput. Sci. 117, 5–50 (2005)] as a logical and semantic framework for lazy Constraint Functional Logic Programming over a parametrically given constraint domain \(\mathcal D\). Further, [F. J. López-Fraguas, M. Rodríguez-Artalejo and R. del Vado Vírseda, “A lazy narrowing calculus for declarative constraint programming”, in: Proceedings of the 6th ACM SIGPLAN international conference on principles and practice of declarative programming, 43–54 (2004)] presented a Constrained Lazy Narrowing Calculus CLNC\((\mathcal D)\) as a convenient computation mechanism for solving goals for CFLP\((\mathcal D)\)-programs, which was proved sound and strongly complete with respect to CFLP\((\mathcal D)\)’s semantics. Now, in order to provide a formal foundation for an efficient implementation of goal solving methods in existing systems such as Curry and \(\mathcal{TOY}\), this paper enriches the CFLP\((\mathcal D)\) framework by presenting an optimization of the CFLNC\((\mathcal D)\) calculus by means of definitional trees to efficiently control the computation. We prove that this new Constrained Demanded Narrowing Calculus CDNC\((\mathcal D)\) preserves the soundness and completeness properties of CLNC\((\mathcal D)\) and maintains the good properties shown for needed and demand-driven narrowing strategies.
For the entire collection see [Zbl 1089.68010].