So it will be possible to create window with 3D graph or spreadsheet and manipulate it (ie. fill cells in spreadsheet, calculate regression and integral of this regression) from lua? It would be wonderful!
Like Orwell said, the spreadsheet will not be available in CPLua. However, regressions and integrals are already available. These are CAS commands, so they can be called by using the "cas" package. The only "problem" is that statistical computations in ClassPad are implemented as commands, not functions. This means that you need to call a statistical command, then access system variables to get the results, just as in CP Basic (this is a CP peculiarity, and has nothing to do with CPLua). For example, the code
require("cas")
cas("OnePropZTest \">\",0.5,15,40")
probability=cas("approx(prob)")performs a one-sample, one-tail hypothesis test of a percentage. The first CAS command calls CP's statistical command "OnePropZTest". After that, the system variable "prob" holds the result (in this example, the so-called "p-value"). Then, the second CAS command assigns the result  to a CPLua variable named "probability". In other words, you always need a couple of CPLua statements in order to perform statistical computations. See the appendix of the CP manual for details about system variables returned by statistical commands.