How can I write a general procedure which will take an integer n and create n nested loops:

add(...(add(f(x_1,...,x_n),i_1=0..k_1),...),i_n=0..k_n);

Thank you in advance.

I have a nested list a := [[1,2,3],[4,5,6],[7,8,9]]: and would like to apply a function f to the 1st elements in nested list, e.g. [[f(1),2,3],[f(4),5,6],[f(7),8,9]]. How can I achieve this?

Thanks in advance.