Comment by bccdee

> Each step modifies state that the next step needs.

I've been bitten by this. It's not the length that's the problem, so much as the surface area which a long function has to stealthily mutate its variables. If you have a bunch of steps in one function all modifying the same state, there's a risk that the underlying logic which determines the final value of widely-used, widely-edited variables can get hard to decipher.

Writing a function like that now, I'd want to make very sure that everything involved is immutable & all the steps are as close to pure functions as I can get them. I feel like it'd get shorter as a consequence of that, just because pure functions are easier to factor out, but that's not really my objective. Maybe step 1 is a function that returns a `Step1Output` which gets stored in a big State object, and step 2 accesses those values as `state.step1Output.x`. If I absolutely must have mutable state, I'd keep it small, explicit, and as separate from the rest of the variables as possible.