There is no NullToken. ObjectToken comes close, since ObjectToken is basically a reference to any Java Object and thus can be of any type.
The data package and type system are covered in http://embedded.eecs.berkeley.edu/concurrency/ptolemy/data.pdf http://embedded.eecs.berkeley.edu/concurrency/ptolemy/type.pdf Page 4 of the type chapter says: "In Ptolemy Classic, the ports on type-polymorphic actors whose types are not specified are said to have ANYTYPE. ANYTYPE ports were allowed to be connected to ports of any other type. However, in the presence of such ports means that type safety cannot be ensured. Instead, Ptolemy II allows ports to have undeclared type, suggesting that the type of those ports has not been determined but cannot be assigned arbitrarily. Instead of being given as constants, the acceptable types on polymorphic actors are described by a set of type constraints. The type checker checks the applicability of a type-polymorphic actor in a model by finding specific types for ports that satisfy the type constraints. This process is called type resolution or type inference, and the specific types are called the resolved types. Assuming the type constraints of actors are consistent with the actor implementation, this technique can ensure the type safety of actor connections." The Synchronous Reactive domain has the notion of absent inputs, I'm not sure if this is what you are getting at. I'm not sure if I've answered your question. . . _Christopher Christopher Brooks (cxh at eecs berkeley edu) University of California Programmer/Analyst Chess/Ptolemy/GSRC US Mail: 558 Cory Hall #1770 ph: 510.643.9841 fax:510.642.2739 Berkeley, CA 94720-1770 home: (F-Tu) 707.665.0131 (W-F) 510.655.5480 (office: 400A Cory) -------- Hi, are there something like NullTokens in Ptolemy which can be converted to an y other type, so that they could be used with any Actor. I'm thinking of a NullToken with type UNKNOWN for example. Thanks Stephan -------- ---------------------------------------------------------------------------- Posted to the ptolemy-hackers mailing list. Please send administrative mail for this list to: [EMAIL PROTECTED]
