Section 5.2.6.2.  CIF++

CIF++ was a small library of classes designed by Peter Murray-Rust during the time that DDL was being developed as a language for representing the properties and attributes of STAR data items (e.g. Murray-Rust, 1993). The purpose of this project was to demonstrate the design of data classes that represented real-world objects such as molecules and crystal cells. At a time when the structure of CIF was under intense discussion, many of the classes were potentially extensible to STAR features that were a superset of those found in CIF.

While these classes were never developed into fully functional applications, they demonstrated a potentially fruitful approach to model representation and gave rise to the idea of including methods in STAR dictionary definitions, thus allowing STAR applications to dynamically associate algorithmic relationships and operations with data objects by parsing the methods description in the dictionary definitions. This approach is currently being developed into a relational expression language for STAR called dREL (Spadaccini et al., 2000).

The ideas behind CIF++ were further developed in a class library for molecular representation called Democritos, and have informed the representation of molecular and crystal structure in Chemical Markup Language (CML) and in the structured document browser Jumbo (Murray-Rust, 1998).

The CIF++ classes have been refactored into Java using the W3C document object model (W3C, 2004) and other DOM-like models. They are now based on an XML schema which is the abstraction of the formal DDL1 specification (Chapter 2.5 ).

These are available as part of the Jumbo distribution at http://cml.sf.net . The design involves an interface that would allow the C++ classes to be recreated from the Java.