Inventing on Principle: Immediate Feedback in Programming Tools

It is HN's go-to recommendation for the case that programming environments should give instant feedback, and it appears in nearly every thread on live coding, visual programming or developer tools.

Bret Victor's talk at CUSEC 2012 in which he argues that creators need immediate feedback and should organize their work around a guiding principle. He demonstrates live-coding and animation tools that show results as you type, and describes his own principle that creators must see what they are making.