This nugget stood out for me: "In my experience most codebases have a pure functional subset, and I believe writing that subset in a pure-functional style is ne

This nugget stood out for me: "In my experience most codebases have a pure functional subset, and I believe writing that subset in a pure-functional style is nearly always a win for the long-term health of the project." This is probably often true. In high level applications, the idea of classing or abstracting out your i/o from the core functionality is appealing from a security and reasoning perspective, but not sure if serious developers think that way. Would you need to understand the rationale behind the codebase from a functional perspective, and even the economics of the business logic behind the features? It's kind of an architects view of "this thing essentially reduces to a queue and if I optimize for this, I get more value."