Bottom-up Programming

Peter Bell's blog is a great guide to domain-specific programming, application frameworks, and DSLs. His article Bottom-Up Programming really captures a style of programming I like. It refers to Paul Graham article that contrasts the old top-down programming style of Structure Programming, and the bottom-up programming often used in LISP. LISP, like Smalltalk, allows you to extend the language itself. LISP programmers would simply add to the language as they needed new features or mechanisms. The resulting solution grew from the bottom up until it could express cleanly and concisely what the domain problem required.

This ties in to the Agile notion of "listening to the code". Code a solution normally and then look at the code for common patterns. Extract those into re-usable classes and components. Repeat. You end up with a framework for building a family of related programs. Most programmers work on related products in a particular area (telephony, graphics, web commerce, whatever), so this framework-building is rarely wasted effort.

Bottom-up programming also ties into Dijkstra's notion that programmers produce about the same number of lines of code regardless of the language. So the higher a level at which you can work, the more productive you can be.

Speakright shares this philosophy. Make a framework which lets programmers write speech apps at a higher level. And able to extend the framework themselves.