<language> (PROGRES) A very high level language based on graph grammars, developed by Andy Scheurr <andy@i3.informatik.rwth-aachen.de> and Albert Zuendorf <albert@i3.informatik.rwth-aachen.de> of RWTH, Aachen in 1991.
PROGRES supports structurally object-oriented specification of attributed graph structures with multiple inheritance hierarchies and types of types (for parametric polymorphism). It also supports declarative/relational specification of derived attributes, node sets, binary relationships (directed edges) and Boolean constraints, rule-oriented/visual specification of parameterised graph rewrite rules with complex application conditions, nondeterministic and imperative programming of composite graph transformations (with built-in backtracking and cancelling arbitrary sequences of failing graph modifications).
It is used for implementing abstract data types with graph-like internal structure, as a visual language for the graph-oriented database GRAS, and as a rule-oriented language for prototyping nondeterministically specified data/rule base transformations.
PROGRES has a formally defined semantics based on "PROgrammed Graph Rewriting Systems". It is an almost statically typed language which additionally offers "down casting" operators for run-time checked type casting/conversion (in order to avoid severe restrictions concerning the language's expressiveness).
Version RWTH 5.10 includes an integrated environment.
[A. Scheurr, "Introduction to PROGRES, an Attribute Graph Grammar Based Specification Language", in Proc WG89 Workshop on Graphtheoretic Concepts in Computer Science", LNCS 411, Springer 1991].
FTP for Sun4.
(02 Nov 1993)