The GP Programming System

We describe the programming system for the graph-transformation language GP, focusing on the implementation of its compiler and abstract machine. We also compare the system's performance with other graph-transformation systems. The GP language is based on conditional rule schemata and comes with a simple formal semantics which maps input graphs to sets of output graphs. The implementation faithfully matches the semantics by using backtracking and allowing to compute all possible results for a given input

The Semantics of Graph Programs

GP (for Graph Programs) is a rule-based, nondeterministic programming language for solving graph problems at a high level of abstraction, freeing programmers from handling low-level data structures. The core of GP consists of four constructs: single-step application of a set of conditional graph-transformation rules, sequential composition, branching and iteration. We present a formal semantics for GP in the style of structural operational semantics. A special feature of our semantics is the use of finitely failing programs to define GP's powerful branching and iteration commands

A Reference Interpreter for the Graph Programming Language GP 2

GP 2 is an experimental programming language for computing by graph transformation. An initial interpreter for GP 2, written in the functional language Haskell, provides a concise and simply structured reference implementation. Despite its simplicity, the performance of the interpreter is sufficient for the comparative investigation of a range of test programs. It also provides a platform for the development of more sophisticated implementations.Comment: In Proceedings GaM 2015, arXiv:1504.0244

De-/Re-constructing Model Transformation Languages

The diversity of today's model transformation languages makes it hard to compare their expressiveness and provide a framework for interoperability. De-constructing and then re-constructing model transformation languages by means of a unique set of most primitive constructs facilitates both. We thus introduce T-Core, a collection of primitives for model transformation. Combining T-Core with a (programming or modelling) language enables the design of model transformation formalisms. We show how basic and more advanced features from existing model transformation languages can be re-constructed using T-Core primitives

The Design of GP 2

This papers defines the syntax and semantics of GP 2, a revised version of the graph programming language GP. New concepts are illustrated and explained with example programs. Changes to the first version of GP include an improved type system for labels, a built-in marking mechanism for nodes and edges, a more powerful edge predicate for conditional rule schemata, and functions returning the indegree and outdegree of matched nodes. Moreover, the semantics of the branching and loop statement have been simplified to allow their efficient implementation.Comment: In Proceedings WRS 2011, arXiv:1204.531