https://www.youtube.com/watch?v=pMGY9ViIGNU
At 9:00 the goal is for the main to read like a lesson in the domain
At 13:30 she shows a different dataflow with functional programming
She consistently talks about pure functions as "data in, data out" and doesn't ever mention "pure" or "no side effects" explicitly, but does infer them.
talk-functional-principles-for-oop#environmental-access-isolated-and-called-out1 2 At 16:45 environmental access is isolated and strictly called out talk-functional-principles-for-oop#environmental-access-isolated-and-called-out1 2
At 19:15 default mutability it is accidental complexity
At 24:30 copy on mod. Sounds a lot like copy on write. She talks about why it's not inefficient to always make copies. The gist is that it can point to other immutable data structures that haven't changed.
talk-functional-principles-for-oop#more-code-ok-if-makes-clearer At 3420 OK with more lines of code as long as it separates application logic from craft craft talk-functional-principles-for-oop#more-code-ok-if-makes-clearer
At 4138 tenant of the main driven design is a universal vocabulary
At 47:10 separate what to do from when to stop