[R] Appropriate method for sharing data across functions

[John C Nash]

Thanks to Hadley, William and Duncan for suggestions. I'm currently implementing a
solution that is close to that of William and Duncan (and learning more about environments
in the process). I suspect the reference classes are possibly a more reliable long term
solution. I'll plead laziness until I find the other approach won't work.

For anyone interested in these issues, over the next few weeks the outcome of my
investigations and trials should be on the SVN repository of R-forge under Optimization
and Solving Tools, https://r-forge.r-project.org/R/?group_id=395, in particular within the
packages optfntools and optimx. However, it will be late April before things stabilize.

John Nash