Techniques editing, as proposed by Sterling et al., allows Prolog programs to be constructed by initially selecting a `skeleton' which determines the flow of control of the program, and then adding on top of this the extra features required by the program. This means that it is easy to obtain as an end-result of techniques editing not only the final program but also a history of its development, in terms of the skeleton and extensions used to build it. We describe how this program history information can be used to produce efficient combined programs from pairs of initial programs constructed independently by a techniques editor. Keywords: techniques editor, classification of Prolog programs, join specification, composition methods, unfold/fold transformations, meta-folding operation, program history. 1 Introduction This paper addresses the combination of two programs constructed by means of a specialised techniques editor, briefly described in Section 2. Currently the techniques edit...

The purpose of this paper is to describe an environment for the construction of complex Prolog programs by combining simpler Prolog programs. The technique consists of the development in parallel of pieces of software which are combined to produce the final program. For producing elegant and efficient programs we need to keep information such as: the kind of program according to a classification effected by considering features of the program and information about history development such as the initial skeleton and techniques that the user applied in the construction of the program. The problem of combining two programs for producing a new program while retaining correctness properties is not an easy problem. Therefore we design a system which provides assistance in deciding how to combine the two programs. The system is based on program transformation, a technique used for optimisation of programs [BD77], supplemented with knowledge of program development. 1 Introduction Several tech...

this paper. References

The purpose of this paper is to describe a mathematical framework which supports our environment for the construction of complex Prolog programs by combining simpler Prolog programs described in [?]. This framework includes three groups of properties: correctness properties which hold after applying each composition method; properties for the type of program which is obtained in each stage of the combining process and properties for the definition of the join specification. Our motivation for providing this framework is to guarantee the soundness of the composition process at the three levels ie. on our methods, on the type of combined program and properties which are useful to the user level. Keywords: skeletons, techniques, extensions, join specification, composition methods, unfold/fold transformations, classification of programs, method properties, extension properties, composition properties. 1 Introduction The idea of stepwise enhancement (as described by Lakhotia et. al. [LS90]...