[R] New function combinations using tree structures?

[Atte Tenkanen]

Hi everybody,

I'm still interesting the possibility to use R for genetic programming (see https://stat.ethz.ch/pipermail/r-help/2007-April/128782.html)
and I'd like to know, how to express for instance this kind of functions (x^2+3x+1 etc, see the picture) using some kind of tree structures and what are needed to make similar recombination operations with them as seen in the picture:

http://users.utu.fi/attenka/Kuva1.png

I know the basic principles of mutation and mating etc, as far as genetic algorithms are concerned, but now I'd like to know the practical issues considering R and mating of these functions using "trees".

All suggestions are warmly appreciated.

With best wishes,

Atte