For DrScheme, semi-structured program editing; an alternative set of key bindings. When it is on, the most important functions can run via unchorded keystrokes, and motion commands work on sexps by default.
His presentation at 1968 Fall Joint Computer Conference, was a live online hypermedia demonstration of pioneering work his group did at SRI. Later called "The Mother of All Demos" by Andy van Dam, this historic show paved the way for modern human-comp...