Is there a way to invoke the expression in a cell (or the data structure it yields), rather than its value?

Someone provided me with a complex formula, that I want to understand and improve.

I started by breaking it apart to see what each part of it yielded, and then chaining the parts to rebuild the whole.

This doesn't work though because some of the parts yield complex data structures rather than simple values.

If there is an expression in say cell E6, I need to be able to refer to that and get the whole data structure it yields, or the expression it contains - is there a way to do that?

For example, let's say that cell E6 contains a formula that returns not just one value, but several values, in a row of cells:

3
5
8
13

If I then do ROWS(E6), I will get only the particular value as displayed in E6 - 3. What I actually want is the whole set of values that the formula returns, so that ROWS(E6) will return 4.