    We plan the follow major extensions to TCM, to be added in the order
    mentioned:

    (1) Addition of hierarchy, so that the enclosure of one node shape by
    another node shape is relevant information. This allows the
    representation of hierarchic statecharts, hierarchic DFDs, hierarchic
    ERDs (with subject areas), packages that enclose other packages or
    classes, etc.

    (2) Addition of global constraints for both YSM and the UML,
    i.e. constraints that involve different diagrams of one coherent
    model.

    (3) Addition of executability for both YSM models and UML
    models. This requires the definition resp. selection of execution
    semantics for both YSM and UML models.These semantics are sketched in
    R.J. Wieringa, ``Design Methods for Reactive Systems: Yourdon,
    Statemate and the UML'', Course Notes, Department of Computer
    Scienced, University of Twente. To implement this, we will have to
    make this semantics precise.

    Interleaved with these major updates, we will continue implementing
    wishes in the wish list that we deem important.

    Currently, we are working with roughly one person-equivalent on
    TCM: Frank Dehne as chief architect,  Henk van de Zandschulp as
    programmer, Roel Wieringa as project leader. Anyone who wants to
    contribute to the GNU version of TCM made available by the University
    of Twente, is welcome to do so. The three people just mentioned will
    take it upon themselves to guarantee consistency and a coherent
    architecture. Please contact tcm@cs.utwente.nl if you plan to
    contribute to TCM.

    You may want to adhere to a strict separation of specification from
    implementation in your extensions of TCM. In the directory
    $TCM_HOME/doc/specs (which is included in the source code distribution)
    you can find some examples of the way we specify our additions to TCM.