Handsontable - Have column level formulas - relative formulas

[Karthik C Sridhar]

There is a way to explicitly write formulas in the data field with absolute cell references like shown here http://handsontable.github.io/handsontable-ruleJS/

However, how do we setup a table to automatically have column level formula with relative values.

For example I want C1 cell to have A1 + B1.

C2 = A2+B2
C3 = A3+B3.

Because when I create & render the table I will have no data. It will be an empty table. When people start entering data into A or B columns the C column should populate automatically. Please let me know how to do this.