And [Brendan Eich] was building SchEme for the browser... And so, Net Scape kinda looked at it, and said: "Yeah, well, we did say Scheme, but, uh, there's this JaVa thing, this giant marketing thing, and we want to be involved with it." And some back-door deals happened, and then they came to Brendan and said: "Make it look like Java."
We've kind of figured out that [Object Oriented Programming] (OOP) doesn't work that well for UI-s. You want it to be Declarat Ive. HTML showed that you want a dialog, with a title bar, and a body, and it nests, to match the (UI) tree.
In a Dynamic Language - and this is clearest when you're writing in EMacs LisP (because of the "scratch" buffer) but it's somewhat clear when you're developing in a console, in PyThon or RuBy, PeRl, LuA, whatever, you write an expression, and you give it some mock data. You're writing a function, you're building it on the fly. And when it works (for that mock data), you're like, "Oh yeah, it works!" You don't run it through a compiler. You copy it and paste it into your Unit Test suite. That's one unit test, right? And you copy it into your code, ok, this is your function.