In this paper we continue previous work from Sannella, Sokolowski and Tarlecki on parameterization in specification languages. Within the loose approach, we define specification and model level semantics for two kinds of parameterizations (parameterized specifications and specifications of parameterized data types) and describe, in a compositional manner, parameter passing at the two levels. Moreover, the specification and the model level semantics of parameter passing are shown to be compatible. We also show that the results obtained do not only apply to the loose approach but can also be directly applicable to the initial framework, and in general to any other kind of monomorphic framework (i.e. a framework where all specifications are monomorphic). In particular, the results obtained generalize and extend previous results for the initial approach. Finally, for obtaining all our results, new categorical constructions of multiple pushouts, amalgamations and extensions, gen...

ions are defined both for objects and layers. There are several compatibility requirements for the definition of these functions. The set of objects contains a specific ?-element which allows the source and target functions to be total on the set of objects. Up to now there exists no implementation of general colimits in the AGG-system. This problem is currently fixed by the integration of the colimit library. Again we can use the colimit computation for Alpha algebras. For this purpose we have to find an Alpha representation of AGG-graphs. Here we will outline the idea. r0 r1 r2 object layer label v0 r4 r0 Item Data The picture above presents a possible Alpha type algebra for AGG-graphs. r 0 ; r 1 and r 2 correspond to the abstraction, source and target functions, r 4 represents the assignment of layers to objects and v 0 is the labelling function. Note that although not shown in the picture, since all references are total, r 1 ; r 2 and r 3 are defined also for layer. This shows ...

: The composition of modular specifications can be modeled, in a category theoretic framework, by colimits of diagrams. Pushouts in particular describe the combination of two specifications sharing a common part. This work extends this classic idea along three lines. First, we define a term language to represent modular specifications built with colimit constructions over a category of base specifications. This language is formally characterized by a finitely cocomplete category. Then, we propose to associate with each term a diagram. This interpretation provides us with a more abstract representation of modular specifications because irrelevant steps of the construction are eliminated. We define a category of diagrams, which is a completion of the base category with finite colimits. We prove that the interpretation of terms as diagrams defines an equivalence between the corresponding categories, which shows the correctness of this interpretation. At last, we propose an algorithm to no...

Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.5.4 Special Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.6 Semantics of Programming Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.1 Semantics of Ada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.6.2 Action Semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 4.7 Specification Languages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.7.1 Early Algebraic Specification Languages . . . . . . . . . . . . . . . . . . . . . . . . 53 4.7.2 Recent Algebraic Specification Languages . . . . . . . . . . . . . . . . . . . . . . . 55 4.7.3 The Common Framework Initiative. . . . . . . . . . . . . . . . . . . . . . . . . . . 56 5 Methodology 57 5.1 Development Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 5.1.1 Applica...