< language > (PROGRES) A very high level language based on graph grammar s, 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 constraint s, 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 type s with graph-like internal structure, as a visual language for the graph-oriented database GRAS , and as a rule-oriented language for prototyping nondeterministic ally 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://ftp.informatik.rwth-aachen.de/pub/Unix/PROGRES/ for Sun-4 .
(1993-11-02)