Simplifying fractions

Question

What ComplexityFunction (or other technique) can I use to have Mathematica pull things out of fractions?

I have a rational function of several variables and I'd like to have Math'ca simplify, e.g.,

x(... + y(... + wz)) + ...
--------------------------
            xyz

to

x(... + y(...)) + ....
---------------------- + w
          xyz

? I've already told it that the relevant variables (in the denominator) are nonzero.

I was thinking of counting complexity as LeafCount plus the LeafCount of numerators, but I'm not sure how to do that.

Answer 1

Murray's suggestion seems to work fine:

eqn = x (5 + a + y (6 + b + w z))/(x y z);
Apart[eqn]

w + (5 + a + 6 y + b y)/(y z)