We are interested in improving the experience of prototyping and implementing programming languages. In this paper, we outline some ways in which principles from live programming could make the life of the “language hacker” easier, and introduce novel visualizations that manifest the normally opaque semantics of parsing and semantic actions. We demonstrate the application of these ideas in the Ohm Editor, a tool we are building to support our new language implementation framework, but we believe they are equally applicable to other language-hacking tools.