[tinco]

I agree that Haskell forces the programmer to create structure, but I don't agree with your meta-problem hypothesis. I think the structure actually is a big part of the real problem, and Haskell just prevents you from implementing incomplete or incorrect solutions.

Those solutions might in another language require a hack or leaky abstractions to work, if they would be possible to get to work at all.

I've walked into problems like the OP has before with Haskell, and when there seems to be no nice way of defining a type structure to model the problem, it usually meant that the idea in my head had a fundamental problem. If I look at this tree I get the feeling that perhaps he just has two problems, and he's looking at it like he's got only one.

And once you do get your type structure neatly in place, often times the implementation will just flow out of your fingertips. And when it does, it will be powerful, flexible and robust.