Just 5 days ago HN was all so negative about Bret Victor's visions[1] of how programming should be taught. And yet here we are, looking at a working example of one of the ideas he wrote about.
My motivation has been to ease the learning path for an existing popular language (Python).
See this 2003 PhD thesis at MIT for two examples of existing languages designed to take full advantage of live programming environments. (Flogo I -graphical- and Flogo II -textual): http://llk.media.mit.edu/papers/ch-phd.pdf Particularly interesting is Flogo II capability to mix the imperative and functional-reactive programming paradigms in the same code block, as parallel runtime processes; I hadn't seen that before.