Thanks for the insightful answer! Building an ecosystem of libraries to do most of the heavy lifting is generally what I strive for as well. It's certainly the goal, and I'll usually end up there for a given project. Perhaps one thing that makes me fond of static types is that, more often than not, I don't actually know how or what to modularize until after the project is nearly built in the first place. And I use types not only as a QA tool, but also as a tool for reasoning. The feedback loop between me encoding logic in types, and the IDE providing me with errors, is a big part of how I understand what I'm building, as I'm building it. I imagine that Clojure development on the REPL can actually serve the same purpose.

I think the idea of bottom-up programming also resonates with me, though I tend to find it hard to use as a general approach to programming. In my mind, it's similar to the development of DSLs, which I do fairly infrequently, and with care. There is an undeniable elegance to it ... find a set of primitive operations that can be composed into larger ones. My development style usually goes in either direction: Either super generalized, for which I'll take the bottom-up DSL approach, or the more typical case where it's more approachable for me to be explicit with types/code.