how to send the current form as parameter to a function

how to send the current form as parameter to a function

Hi there,

I have a form where several fields need to be recalculated everytime several other fields are changed.
Thus I would like to have a function that will take the current form as a parameter and gather input data, recalculate and re-populate fields with new result.

However I cant figure out how to send the current form as a parameter - I can send the datatable so I can get access to the input fields, but I cannot change the value of existing fields through the function ?!

Can anyone point me in the right direction ?

Thanks in advance,
David