Abstract visual syntax

... syntax, much like it is often done for textual languages. Here the focus is on visual programming languages; the impact on visual languages in general is not clear by now. We suggest to use unstructured labeled multi-graphs as abstract visual syntax and show how this facilitates semantics definitions and transformations of visual syntax level makes such manipulations simple and powerful. Moreover, we demonstrate that – in contrast to the traditional monolithic graph definition – an inductive view of graphs provides a very convenient way to move in a structured (and declarative) way through graphs. Again this supports the simplicity of descriptions for transformations and semantics