  Applied research in graph algorithms and combinatorial structures needs
comprehensive and versatile software libraries. However, the design and the
implementation of flexible libraries are challenging activities. Among the
other problems involved in such a difficult field, a very special role is
played by graph classification issues.
  We propose new techniques devised to help the designer and the programmer in
the development activities. Such techniques are especially suited for dealing
with graph classification problems and rely on an extension of the usual
object-oriented paradigm. In order to support the usage of our approach, we
devised an extension of the C++ programming language and implemented the
corresponding pre-compiler.
