Abstract not found

The term rule-based program is meant to include definite clause programs, SOS specifications, attribute grammars, and conditional rewrite systems. These setups are widely used for the executable specification or implementation of language-based tools, e.g., interpreters, translators, type checkers, program analysers, and program transformations. We provide a pragmatic, transformation-based approach for expressing and tracking changes in rule-based programs in the course of program evolution. To this end, we design an operator suite for the transformation of rule-based programs. The operators facilitate steps for clean-up, refactoring, and enhancement. We use SOS-based interpreter examples to illustrate evolution of rule-based programs. We use logic programming to execute the examples, while the relevant evolution operators are made available as logic meta-programs.

minitalk is a simple object-oriented functional programming language. We report on its design and comment a formal and executable language definition which can be applied in the \Delta system. The essential motivation for the design of minitalk have been to consider an object-oriented programming language with a simple operational semantics. This experiment serves as an annotated example of an \Delta specification. It might be useful in the context of teaching semantics of object-oriented languages. Contents 1 Introduction 2 2 Sources 3 2.1 examples/minitalk/main.pra . . . . . . . . . . . . . . . . . . . . . 3 2.2 examples/minitalk/analyser.gs . . . . . . . . . . . . . . . . . . . 4 2.3 examples/minitalk/scanner.lg . . . . . . . . . . . . . . . . . . . . 7 2.4 examples/minitalk/dynamic.ir . . . . . . . . . . . . . . . . . . . . 8 2.5 examples/minitalk/new.ir . . . . . . . . . . . . . . . . . . . . . . 10 2.6 examples/minitalk/lookup.ir . . . . . . . . . . . . . . . . . . . . . 10 2....