Michael Ballantyne is a PhD student at the Northeastern University Programming Research Laboratory, advised by Matthias Felleisen. He envisions a future where mainstream programmers regularly create, extend, and fluidly intermix domain-specific languages, with excellent support from their programming language and environment. Recently he’s been developing a formal characterization of macro hygiene that accounts for the full range of program transformations used in embedded DSL implementation, and also improving the type systems as macros approach to integrate macro expansion and typechecking.