Logic programming in the context of multiparadigm programming: the Oz experience

Oz is a multiparadigm language that supports logic programming as one of its major paradigms. A multiparadigm language is designed to support different programming paradigms (logic, functional, constraint, object-oriented, sequential, concurrent, etc.) with equal ease. This article has two goals: to give a tutorial of logic programming in Oz and to show how logic programming fits naturally into the wider context of multiparadigm programming. Our experience shows that there are two classes of problems, which we call algorithmic and search problems, for which logic programming can help formulate practical solutions. Algorithmic problems have known efficient algorithms. Search problems do not have known efficient algorithms but can be solved with search. The Oz support for logic programming targets these two problem classes specifically, using the concepts needed for each. This is in contrast to the Prolog approach, which targets both classes with one set of concepts, which results in less than optimal support for each class. To explain the essential difference between algorithmic and search programs, we define the Oz execution model. This model subsumes both concurrent logic programming (committed-choice-style) and search-based logic programming (Prolog-style). Instead of Horn clause syntax, Oz has a simple, fully compositional, higher-order syntax that accommodates the abilities of the language. We conclude with lessons learned from this work, a brief history of Oz, and many entry points into the Oz literature.Comment: 48 pages, to appear in the journal "Theory and Practice of Logic Programming

The Resource constrained shortest path problem implemented in a lazy functional language

The resource constrained shortest path problem is an NP-hard problem for which many ingenious algorithms have been developed. These algorithms are usually implemented in FORTRAN or another imperative programming language. We have implemented some of the simpler algorithms in a lazy functional language. Benefits accrue in the software engineering of the implementations. Our implementations have been applied to a standard benchmark of data files, which is available from the Operational Research Library of Imperial College, London. The performance of the lazy functional implementations, even with the comparatively simple algorithms that we have used, is competitive with a reference FORTRAN implementation

A Generalized Model for Algorithmic Debugging

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-27436-2_16Algorithmic debugging is a semi-automatic debugging technique that is present in practically all mature programming languages. In this paper we claim that the state of the practice in algorithmic debugging is a step forward compared to the state of the theory. In particular, we argue that novel techniques for algorithmic debugging cannot be supported by the standard internal data structures used in this technique, and a generalization of the standard definitions and algorithms is needed. We identify two specific problems of the standard formulation and implementations of algorithmic debugging, and we propose a reformulation to solve both problems. The reformulation has been done in a paradigm-independent manner to make it useful and reusable in different programming languages.This work has been partially supported by the EU (FEDER) and the Spanish Ministerio de Economía y Competitividad (Secretaría de Estado de Investigación, Desarrollo e Innovación) under Grant TIN2013-44742-C4-1-R and by the Generalitat Valenciana under Grant PROMETEOII/2015/013. David Insa was partially supported by the Spanish Ministerio de Educación under FPU Grant AP2010-4415.Insa Cabrera, D.; Silva Galiana, JF. (2015). A Generalized Model for Algorithmic Debugging. En Logic-Based Program Synthesis and Transformation. Springer. 261-276. https://doi.org/10.1007/978-3-319-27436-2_16261276Eclipse (2003). http://www.eclipse.org/Barbour, T., Naish, L.: Declarative debugging of a logical-functional language. Technical report, University of Melbourne (1994)Braßel, B., Siegel, H.: Debugging lazy functional programs by asking the oracle. In: Chitil, O., Horváth, Z., Zsók, V. (eds.) IFL 2007. LNCS, vol. 5083, pp. 183–200. Springer, Heidelberg (2008)Caballero, R.: A declarative debugger of incorrect answers for constraint functional-logic programs. In: Proceedings of the 2005 ACM-SIGPLAN Workshop on Curry and Functional Logic Programming (WCFLP 2005), pp. 8–13. ACM Press, New York, USA (2005)Caballero, R., Martin-Martin, E., Riesco, A., Tamarit, S.: EDD: A declarative debugger for sequential erlang programs. In: Ábrahám, E., Havelund, K. (eds.) TACAS 2014 (ETAPS). LNCS, vol. 8413, pp. 581–586. Springer, Heidelberg (2014)Caballero, R., Riesco, A., Verdejo, A., Martí-Oliet, N.: Simplifying questions in maude declarative debugger by transforming proof trees. In: Vidal, G. (ed.) LOPSTR 2011. LNCS, vol. 7225, pp. 73–89. Springer, Heidelberg (2012)Cheda, D., Silva, J.: State of the practice in algorithmic debugging. Electron. Notes Theor. Comput. Sci. 246, 55–70 (2009)Davie, T., Chitil, O.: Hat-delta: one right does make a wrong. In: Butterfield, A., (ed.) Proceedings of the 17th International Workshop on Implementation and Application of Functional Languages (IFL 2005), p. 11, September 2005Davie, T., Chitil, O.: Hat-delta: One right does make a wrong. In: Proceedings of the 7th Symposium on Trends in Functional Programming (TFP 2006), April 2006Fritzson, P., Shahmehri, N., Kamkar, M., Gyimóthy, T.: Generalized algorithmic debugging and testing. ACM Lett. Program. Lang. Syst. (LOPLAS) 1(4), 303–322 (1992)González, J., Insa, D., Silva, J.: A new hybrid debugging architecture for eclipse. In: Gupta, G., Peña, R. (eds.) LOPSTR 2013, LNCS 8901. LNCS, vol. 8901, pp. 183–201. Springer, Heidelberg (2014)Hermanns, C., Kuchen, H.: Hybrid debugging of java programs. In: Escalona, M.J., Cordeiro, J., Shishkov, B. (eds.) ICSOFT 2011. CCIS, vol. 303, pp. 91–107. Springer, Heidelberg (2013)Insa, D., Silva, J.: An algorithmic debugger for java. In: Proceedings of the 26th IEEE International Conference on Software Maintenance (ICSM 2010), pp. 1–6 (2010)Insa, D., Silva, J.: Automatic transformation of iterative loops into recursive methods. Inf. Soft. Technol. 58, 95–109 (2015)Insa, D., Silva, J., Riesco, A.: Speeding up algorithmic debugging using balanced execution trees. In: Veanes, M., Viganò, L. (eds.) TAP 2013. LNCS, vol. 7942, pp. 133–151. Springer, Heidelberg (2013)Insa, D., Silva, J., Tomás, C.: Enhancing declarative debugging with loop expansion and tree compression. In: Albert, E. (ed.) LOPSTR 2012. LNCS, vol. 7844, pp. 71–88. Springer, Heidelberg (2013)Lloyd, J.: Declarative error diagnosis. New Gener. Comput. 5(2), 133–154 (1987)Lux, M.: Münster Curry User’s Guide, May 2006. http://danae.uni-muenster.de/lux/curry/user.pdf ,MacLarty, I.D.: Practical Declarative Debugging of Mercury Programs. Ph.D. thesis, University of Melbourne (2005)Naish, L., Dart, P.W., Zobel, J.: The NU-Prolog debugging environment. In: Porto, A. (ed.) Proceedings of the 6th International Conference on Logic Programming (ICLP 1989), pp. 521–536. Lisboa, Portugal (1989)Nilsson, H.: Declarative Debugging for Lazy Functional Languages. Ph.D. thesis, Linköping, Sweden, May 1998Nilsson, H.: How to look busy while being as lazy as ever: the implementation of a lazy functional debugger. J. Funct. Program. 11(6), 629–671 (2001)Nilsson, H., Fritzson, P.: Algorithmic debugging for lazy functional languages. J. Funct. Program. 4(3), 337–370 (1994)Nilsson, H., Sparud, J.: The evaluation dependence tree: an execution record for lazy functional debugging. Technical report, Department of Computer and Information Science, Linköping (1996)Nilsson, H., Sparud, J.: The evaluation dependence tree as a basis for lazy functional debugging. Autom. Softw. Eng. 4(2), 121–150 (1997)Pope, B.: A Declarative Debugger for Haskell. Ph.D. thesis, The University of Melbourne, Australia (2006)Shapiro, E.: Algorithmic Program Debugging. MIT Press, Cambridge (1982)Shapiro, E.Y.: Inductive inference of theories from facts. Technical report RR 192, Yale University (New Haven, CT US) (1981)Silva, J.: A survey on algorithmic debugging strategies. Adv. Eng. Softw. 42(11), 976–991 (2011)Silva, J.: A vocabulary of program slicing-based techniques. ACM Comput. Surv. 44(3), 1–12 (2012)Thompson, B., Naish, L.: A guide to the nu-prolog debugging environment. Technical report, University of Melbourne (1997

Optimizing Abstract Abstract Machines

The technique of abstracting abstract machines (AAM) provides a systematic approach for deriving computable approximations of evaluators that are easily proved sound. This article contributes a complementary step-by-step process for subsequently going from a naive analyzer derived under the AAM approach, to an efficient and correct implementation. The end result of the process is a two to three order-of-magnitude improvement over the systematically derived analyzer, making it competitive with hand-optimized implementations that compute fundamentally less precise results.Comment: Proceedings of the International Conference on Functional Programming 2013 (ICFP 2013). Boston, Massachusetts. September, 201

An Integrated Development Environment for Declarative Multi-Paradigm Programming

In this paper we present CIDER (Curry Integrated Development EnviRonment), an analysis and programming environment for the declarative multi-paradigm language Curry. CIDER is a graphical environment to support the development of Curry programs by providing integrated tools for the analysis and visualization of programs. CIDER is completely implemented in Curry using libraries for GUI programming (based on Tcl/Tk) and meta-programming. An important aspect of our environment is the possible adaptation of the development environment to other declarative source languages (e.g., Prolog or Haskell) and the extensibility w.r.t. new analysis methods. To support the latter feature, the lazy evaluation strategy of the underlying implementation language Curry becomes quite useful.Comment: In A. Kusalik (ed), proceedings of the Eleventh International Workshop on Logic Programming Environments (WLPE'01), December 1, 2001, Paphos, Cyprus. cs.PL/011104