> I've heard this about Lisp, but I don't really get how this doesn't apply to other languages. It can be, and he even says as much: >> Bottom-up design is po

> I've heard this about Lisp, but I don't really get how this doesn't apply to other languages. It can be, and he even says as much: >> Bottom-up design is possible to a certain degree in languages other than Lisp. Whenever you see library functions, bottom-up design is happening. I'll also point to kazinator's quote of Ken Thompson in the previous discussion linked by dang: >> It is the way I think. I am a very bottom-up thinker. If you give me the right kind of Tinker Toys, I can imagine the building. I can sit there and see primitives and recognize their power to build structures a half mile high, if only I had just one more to make it functionally complete. I can see those kinds of things. The converse is true, too, I think. I can’t— from the building—imagine the Tinker Toys. When I see a top-down description of a system or language that has infinite libraries described by layers and layers, all I just see is a morass. I can’t get a feel for it. I can’t understand how the pieces fit; I can’t understand something presented to me that’s very complex. Maybe I do what I do because if I built anything more complicated, I couldn’t understand it. I really must break it down into little pieces. - Ken Thompson, Unix and Beyond: An Interview with Ken Thompson, 1999 And if you use a TDD style of development (in particular, but test-heavy in general with frequent use of unit and integration tests below the full end-to-end-test level) you'll also likely stumble onto a similar bottom-up style of development. I think, circa 1993, his emphasis on Lisp and bottom-up development made a lot more sense than it does today with the increasing availability of interactive development environments (essentially every dynamically typed language, pretty much; but even many others like Java and C#) and increased emphasis on test-heavy development methodologies.