Showing papers by "Antonio Brogi published in 1998"
TL;DR: The notion of modular embedding introduced by De Boer and Palamidessi in [3] is used to compare the relative expressive power of the languages and it is shown that the language containing all the communication primitives considered is strictly more expressive than each of its sub-languages, except for the redundancy of ask.
34 citations
15 Jun 1998
TL;DR: The role of renaming as a key ingredient of component-based programming is analysed and a meta-level renaming operation is introduced in the context of a logic-based program composition setting which features a number of other composition operations over general logic programs, that is, logic programs possibly containing negative premises.
Abstract: Most modern computing systems consist of large numbers of software components that interact with each other. Correspondingly, the capability of re-using and composing existing software components is of primary importance in this scenario. In this paper we analyse the role of renaming as a key ingredient of component-based programming. More precisely, a meta-level renaming operation is introduced in the context of a logic-based program composition setting which features a number of other composition operations over general logic programs, that is, logic programs possibly containing negative premises. Several examples are presented to illustrate the increased knowledge representation capabilities of logic programming for non-monotonic reasoning. The semantics of programs and program compositions is defined in terms of three-valued logic by extending the three-valued semantics for logic programs proposed by Fitting [10]. A computational interpretation of program compositions is formalised by means of an equivalence preserving transformation of arbitrary program compositions into standard general programs.
5 citations
TL;DR: The design and implementation of declarative program specialiser is described that suitably transforms meta-interpreters implementing compositions of object programs so as to sensibly reduce — if not to completely remove — the overhead due to the handling of program compositions.
Abstract: Meta-level compositions of object logic programs are naturally implemented by means of meta-programming techniques. Meta-interpreters defining program compositions however suffer from a computational overhead that is due partly to the interpretation layer present in all meta-programs, and partly to the specific interpretation layer needed to deal with program compositions. We show that meta-interpreters implementing compositions of object programs can be fruitfully specialised w.r.t. meta-level queries of the form "Demo(E,G)", where "E" denotes a program expression and "G" denotes a (partially instantiated) object level query. More precisely, we describe the design and implementation of a declarative program specialiser that suitably transforms such meta-interpreters so as to sensibly reduce --- if not to completely remove --- the overhead due to the handling of program compositions. In many cases the specialiser succeeds in eliminating also the overhead due to meta-interpretation.
4 citations