Define your variables
Here you define the variables that you want to use in your calculation.
pat_weight = 80; pat_height = 1.80;
Please note, if you are using dates, you need to add quotation marks, e.g.:
inc_date = "20-05-2016";
Here you write your calculation field template just as you would in Castor.
If there are any issues with your script, they will appear here.
This is what your final formula will look like.
This is the output of the calculation.