G. Puebla, F. Bueno, and M. Hermenegildo, "A Framework for Assertion-based Debugging in Constraint Logic Programming", Proceedings of the International Conference on Principles and Practice of Constraint Programming, number 1520 in LNCS, June 1993, pp. 472-473.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....However, in this method the drawback is that the correct version of the code may not be always available. There are also other approaches where the software developer is forced to avoid errors during coding. This is provided by constraints defined inside the program code in the form of assertions [3]. Assertions are linguistic constructions which allow either run time checking or compile time checking of constraints defined in the programs. Going one step further, some logic programming languages have been developed depending on the assertion methodology such as Godel [4] and Mercury [5] ....

G. Puebla, F. Bueno, and M. Hermenegildo, "A Framework for Assertion-based Debugging in Constraint Logic Programming", Proceedings of the International Conference on Principles and Practice of Constraint Programming, number 1520 in LNCS, June 1993, pp. 472-473.

....are also disussed in Section 6. Related Work A number of proposals to explain the results of query evaluation of logic programs have been put forth in the past. These include algorithmic debugging techniques [10] declarative debugging techniques [4, 6] assertion based debugging techniques [7], and explanation techniques [5] A more detailed comparison between justi cation and these aproaches appears in our earlier work [8] Suce it is say here that although justi cation is similar in spirit to the above approaches in terms of their objectives it di ers considerably from all them. It ....

G. Puebla, F. Bueno, and M. Hermenegildo. A framework for assertion-based debugging in constraint logic programming. In Pre-proceedings of LOPSTR, 1999.

....goal is present in some related works: Anna [11] is an Ada extension that includes facilities for formally specifying the intended behaviour of Ada programs, and the runtime checking of them. The assertions are limited to Ada constructions and they work mainly with algebraic speci cations. In [14] a framework for assertion based debugging is presented: assertions are written using Prolog and a type language so the user cannot specify properties in such an abstract way as in SLAM. Other related works are the result checking approach [2] the user must specify a new algorithm in order to ....

G. Puebla, F. Bueno, and M. Hermenegildo. A Framework for Assertion-based Debugging in Constraint Logic Programming. In Proceedings of the JICSLP'98 Workshop on Types for CLP, Manchester, UK, June 1998.

....subset of SLAM features. The discussion of full SLAM is beyond the aims of the paper and can be found in the SLAM webpage [15] We focus on the most significant SLAM features and how to obtain the Prolog code to check the assertions. The translation from SLAM to Prolog is fully formalized. In [12] a framework for assertion based debugging is presented, in this work assertions are written using Prolog and a type language so the user cannot specify properties in such an abstract way as in SLAM. Other related work is [1] but in this case the user must specify a new algorithm in order to ....

G. Puebla, F. Bueno, and M. Hermenegildo. A Framework for Assertion-based Debugging in Constraint Logic Programming. In Proceedings of the JICSLP'98 Workshop on Types for CLP, Manchester, UK, June 1998.

....by SLD resolution. Declarative debugging techniques [17, 20] assume a user provided intended model of the given program and then attempt to explain the unexpected success failure of a query by nding a program clause which is false in the intended model. Assertion based debugging techniques [22] perform program validation and debugging by static and dynamic checking of user provided assertions (which are essentially partial speci cation of the intended model of the program) Although justi cation is similar in spirit to the above 2 approaches in terms of their objectives it di ers ....

G. Puebla, F. Bueno, and M. Hermenegildo. A framework for assertion-based debugging in constraint logic programming. In Pre-proceedings of LOPSTR, 1999.

....to work with other CLP languages, as we have isolated its parts responsible for the built ins of CHIP. The prototype has been implemented in CHIP and has been ported to SICStus Prolog and CIAO [CLI97] The latter implementation is a part of an assertion based framework for debugging in CLP [PBM98]. The system presents types to the user as regular term grammars, which are more easily comprehensible than RULC programs. This provides a restricted but useful kind of polymorphism (conf. Section 5) A subject for future work is obtaining more precise analysis by using a more sophisticated ....

G. Puebla, F. Bueno, and Hermenegildo M. A framework for assertionbased debugging in constraint logic programming. In proceedings of Types for Constraint Logic Programming, post-conference workshop of JICSLP'98, 1998.

....selecting an analysis that uses the same type system as abstract domain and providing sufficient (type) assertions in the program. Informally, the actual checking of the assertions at compile time is performed as follows (precise details on how to reduce assertions at compile time can be found in [37]) The properties which appear in the user provided check assertions are compared one by one with the properties inferred by the analysis. An assertion is validated if all its properties are implied by the analysis results (preconditions require special consideration in this process) On the other ....

.... can be recognized at compile time) If a property appearing in an assertion is native of an analysis then it is often possible to either prove it or disprove it, provided that the analysis is accurate enough and the direction of approximation performed by the analysis is the appropriate one [37,10] (this is the case for the properties var and does not fail in the example above) We say that the properties are abstractly reducible (to either true or false) or abstractly executable [39] Note that, if the analysis is precise (in the sense that the abstract operations do not lose information ....

[Article contains additional citation context not shown here]

G. Puebla, F. Bueno, and M. Hermenegildo. A Framework for Assertion-based Debugging in Constraint Logic Programming. In Proceedings of the JICSLP'98 Workshop on Types for CLP, Manchester, UK, June 1998.

....are optional. In particular, we do not wish to limit the programming language or the language of assertions unnecessarily in order to make the assertions statically decidable. Consequently, the proposed framework needs to deal throughout with approximations [2] The framework we propose (see [4]) is aimed at detecting deviations of the program behavior (symptoms) w.r.t. the given assertions, either statically (at compile time) or dynamically (at run time) Our approach is strongly motivated by the availability of analyzers for constraint logic programs which can statically infer a wide ....

....in the program for checking assertions at run time. Both the static and the dynamic checking are provably safe in the sense that all errors agged are de nite violations of the speci cations. A preliminary implementation and evaluation of the framework has been performed. Details can be found in [4]. ....

G. Puebla, F. Bueno, and M. Hermenegildo. A Framework for Assertion-based Debugging in Constraint Logic Programming. In Proceedings of the JICSLP'98 Workshop on Types for CLP, pages 3-15, Manchester, UK, June 1998.

.... the analyzer for example as follows: trust pred geq(X,Y) ground(X) ground(Y) trust pred lt(X,Y) ground(X) ground(Y) Finally, assertions with a check pre x can be used to specify the intended semantics of the program, which can then be used in debugging and or validation [19, 20], as we will see in Section 3. The same assertions are also used to generate documentation automatically [17] Assertions refer to certain program points. The true pred assertions above specify in a combined way properties of both the entry (i.e. upon calling) and exit (i.e. upon success) points ....

....for all calls to a predicate. Properties of successes can be restricted to apply only to calls satisfying certain properties upon entry by adding a : eld to success assertions (see [19] Ciaopp can check the assertions above, by comparing them with the assertions inferred by analysis (see [3, 20] for details) producing: checked calls qsort(A,B) list(A,num) A1 : check success qsort(A,B) sorted num list(B) A2 : checked calls partition(A,B,C,D) ground(A) ground(B) A3 : checked success partition(A,B,C,D) list(C,num) ground(D) A4 : false calls append(A,B,C) ....

G. Puebla, F. Bueno, and M. Hermenegildo. A Framework for Assertionbased Debugging in Constraint Logic Programming. In Logic-based Program Synthesis and Transformation (LOPSTR'99), Venezia, Italy, September 1999.

....selecting an analysis that uses the same type system as abstract domain and providing sufficient (type) assertions in the program. Informally, the actual checking of the assertions at compile time is performed as follows (precise details on how to reduce assertions at compile time can be found in [32]) The properties which appear in the user provided check assertions are compared one by one with the properties inferred by the analysis. An assertion is validated if all its properties are implied by the analysis results (preconditions require special consideration in this process) On the other ....

.... this can be recognized at compile time) If a property appearing in an assertion is native of an analysis then it is often possible to either prove it or disprove it, provided that the analysis is accurate enough and the direction of approximation performed by the analysis is the appropriate one [32, 10] (this is the case of the properties var and does not fail in the example above) Also, if the analysis is precise (in the sense that the abstract operations do not lose information beyond the abstraction implied by the abstraction function used [14] then whether such properties hold or not will ....

[Article contains additional citation context not shown here]

G. Puebla, F. Bueno, and M. Hermenegildo. A Framework for Assertion-based Debugging in Constraint Logic Programming. In Proceedings of the JICSLP'98 Workshop on Types for CLP, Manchester, UK, June 1998.

....Chapter 6 Implementation issues This chapter surveys some details and main design decisions of the prototype implementation of the analyzer and the diagnoser. The current version of the prototype has been implemented in CHIP [Cos96] The analyzer has been also ported to SICStus Prolog and CIAO [CLI97, PBH98]. Section 6.4 shows the graphical user interface of the entire system which integrates both the analyzer and the diagnoser. 6.1 The analyzer First step performed by the analyzer is transforming an input program P to a program P CS of proposition 2.4.2 or to verification conditions of ....

....current version is implemented for the programming language CHIP. We expect it to be easily portable to analyze other CLP languages, as we have isolated its parts which are specific for CHIP. The prototype of the analyzer has been implemented in CHIP and has been ported to SICStus Prolog and CIAO [CLI97, PBH98]. The system presents types to the user as regular term grammars, which are more easily comprehensible than RULC programs. It provides a restricted but useful kind of polymorphism (cf. Section 3.6) We also show how to perform incorrectness diagnosis based on the inferred type information. The ....

G. Puebla, F. Bueno, and M. Hermenegildo. A framework for assertion-based debugging in constraint logic programming. In proceedings of Types for Constraint Logic Programming, postconference workshop of JICSLP'98, 1998.

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