Function Objects
Here are some examples demonstrating how function objects can be used to 
  -  transform a matrix A into another matrix B 
    which is a function of the original matrix A (and optionally yet another matrix 
    C)
-  aggregate cell values or a function of them
-  generate selection views for cells satisfying 
    a given condition
-  sort matrix rows or columns into a user specified 
    order
- You will most likely use them to do many more powerful things