You put into words what I couldn't put my finger on about functional programming. With my introduction to ruby and prototype (over C), I'm finally understanding

You put into words what I couldn't put my finger on about functional programming. With my introduction to ruby and prototype (over C), I'm finally understanding the mathematical-monadic-compositional aspect to functional programming that makes it so powerful. Its not even what you do with it - its the emergent behavior that makes it so compelling. Basically what I think you've summed up (but in less words) is that this is a proof-of-concept or a building-block for much more sophisticated examples, showing real approaches of building complex and powerful (especially the UI based expression analyzer) web applications with amazingly little code.