Thank you Manfred. [...]
Looks like an awful lot of repetition, and would have to take a closer look at your problem for advice on design. However, to get you going, below is the Boost.PP work to do what you want - but think even that could be done better..
This is the design of the lib I use. The class I need is templated and policy based. Usually, when I know the instanciation I would like to have, I define a typedef and use it in the rest of the programm. Now, to be more generic, the programm need to let a user choose how to instanciate the class. If you have any idea about a better design, I will be very interesting in reading it. Best regards, Olivier -- Dr. Olivier Tournaire MATIS - Institut Géographique National 73, Ave de Paris 94165 St Mandé cedex, France tel: (+33) 1 43 98 80 00 - 71 25 fax: (+33) 1 43 98 85 81