Dinesh, T., Susan Uskudarli. Share-where maintenance in visual algebraic specifications. In Advances in Computing Science ? ASIAN'97. Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, 1997. [doi]
Algebraic specifications whose signatures (abstract-syntax) have a mapping to pictures (two-dimensional concrete syntax) along with equations which are defined in terms of these pictures are introduced as visual algebraic specifications. The visual signatures are specified using visual lexicals which may be user-defined. The semantic rules are a set of equations which are defined using the language’s own syntax. Signatures, semantic rules, and terms (programs) are all defined with interactive editors. The usual notion of term construction in an editor is extended by allowing subterm sharing which is necessary for two-dimensional representations. As is usual for algebraic specifications, we use term rewriting to provide a prototyping environment for these visual algebraic specifications. This work addresses the problem of presenting output terms after rewriting (visual pretty printing). We introduce a technique called Share-Where Maintenance which is used to preserve layout information and demonstrate its use as well as its limitations.