Source : Free On-Line Dictionary of Computing

PROgrammed Graph REwriting Systems
     
         (PROGRES) A very high level language based on
        {graph grammar}s, developed by Andy Scheurr
         and Albert Zuendorf
         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)