We present an approach for the generation of components for a software renovation factory. These components are generated from a context-free grammar definition that recognizes the code that has to be renovated. We generate analysis and transformation components that can be instantiated with a specific transformation or analysis task. We apply our approach to COBOL and we discuss the construction of realistic software renovation components using our approach.

So-called little,ordomain-specific languages (DSLs), have the potential to make software maintenance simpler: domain-experts can directly use the DSL to make required routine modifications. On the negative side, however, more substantial changes may become more difficult: such changes may involve altering the domain-specific language. This will require compiler technology knowledge, which not every commercial enterprise has easily available. Based on experience taken from industrial practice, we discuss the role of DSLs in software maintenance, the dangers introduced by using them, and techniques for controlling the risks involved.

Application programmer’s interfaces give access to domain knowledge encapsulated in class libraries without providing the appropriate notation for expressing domain composition. Since object-oriented languages are designed for extensibility and reuse, the language constructs are often sufficient for expressing domain abstractions at the semantic level. However, they do not provide the right abstractions at the syntactic level. In this paper we describe MetaBorg, a method for providing concrete syntax for domain abstractions to application programmers. The method consists of embedding domain-specific languages in a general purpose host language and assimilating the embedded domain code into the surrounding host code. Instead of extending the implementation of the host language, the assimilation phase implements domain abstractions in terms of existing APIs leaving the host language undisturbed. Indeed, Meta-Borg can be considered a method for promoting APIs to the language level. The method is supported by proven and available technology, i.e. the syntax definition formalism SDF and the program transformation language and toolset Stratego/XT. We illustrate the method with applications in three domains: code generation, XML generation, and user-interface construction.

Meta programs manipulate structured representations, i.e., abstract syntax trees, of programs. The conceptual distance between the concrete syntax meta-programmers use to reason about programs and the notation for abstract syntax manipulation provided by general pur- pose (meta-) programming languages is too great for many applications. In this paper it is shown how the syntax definition formalism SDF can be employed to fit any meta-programming language with concrete syn- tax notation for composing and analyzing object programs. As a case study, the addition of concrete syntax to the program transformation language Stratego is presented. The approach is then generalized to arbitrary meta-languages.

Term rewriting is an appealing technique for performing program analysis and program transformation. Tree (term) traversal is frequently used but is not supported by standard term rewriting.

Architecture The Alma Abstract Architecture (AAA) is the virtual architecture used during the intermediate code generation phase of the Alma-0 compiler. The AAA combines the features of the abstract machines for imperative languages and for logic programming languages. The compiler compiles the Alma-0 programs into AAA programs. In a second phase the AAA instructions are translated into C statements. As the Alma-0 language itself, the AAA aims to combine the best of both worlds; elements were taken from virtual machines used to compile imperative languages (in particular the RISC architecture described in Wirth [1996, pp. 55--59], and from the WAM machine used to compile a logical language (see Ait-Kaci [1991]). Still, the AAA resembles most the virtual machines used in the compilation of imperative languages. The additions made to provide for the extensions of the Alma-0 language are ---the failure handling instructions ONFAIL, FAIL, 40 \Delta Krzysztof R. Apt et al ---the log ...

We proposed a new approach for the construction of grammars and parsers for existing languages. The approach is both very powerful and simple. We provided a structured process and explained our methods in detail so that others can apply our ideas for their own grammar construction activities. We illustrated the proposed approach with a nontrivial case study. Using our process, we constructed in a few weeks a complete and correct VS COBOL II grammar specification for IBM mainframes. We not only constructed a parser for it, but also published a web-enabled grammar specification so that others can use this result to conveniently construct their own grammar-based tools for VS COBOL II, or derivatives.

Stratego is a language for the specification of transformation rules and strategies for applying them. The basic actions of transformations are matching and building instantiations of first-order term patterns. The language supports concise formulation of generic and data type-specific term traversals. One of the unusual features of Stratego is the separation of scope from matching, allowing sharing of variables through traversals. The combination of first-order patterns with strategies forms an expressive formalism for pattern matching. In this paper we discuss three examples of strategic pattern matching: (1) Contextual rules allow matching and replacement of a pattern at an arbitrary depth of a subterm of the root pattern. (2) Recursive patterns can be used to characterize concisely the structure of languages that form a restriction of a larger language. (3) Overlays serve to hide the representation of a language in another (more generic) language. These techniques are illustrated by...

. Renovation of business-critical software is becoming increasingly important. We identify fundamental notions and techniques to aid in system renovation and sketch some basic techniques: generic language technology to build analysis tools, a knowledge retrieval system to aid in program understanding, and a coordination architecture that is useful to restructure monolithic systems thus enabling their renovation. We argue that these techniques are not only essential for the renovation of old software but that they can also play an important role during the development and maintenance of new software systems. Categories and Subject Description: D.2.6 [Software Engineering]: Programming Environments---Interactive; D.2.7 [Software Engineering]: Distribution and Maintenance ---Restructuring; D.2.m [Software Engineering]: Miscellaneous---Rapid prototyping; D.3.2 [Programming Languages]: Language Classifications---Specialized application languages; E.2 [Data]: Data Storage Representations---C...

Generic language technology and compiler construction techniques are a prerequisite to build analysis and conversion tools that are needed for the re-engineering of large software systems. We argue that generic language technology is a crucial means to do fundamental re-engineering. Furthermore, we address the issue that the application of compiler construction techniques in re-engineering generates new research questions in the field of compiler construction.