Well, there's always the "Ometa" approach/extension to PEGs - the author works(?) at now y-combinator sponsored research into language design (not sure if he's

Well, there's always the "Ometa" approach/extension to PEGs - the author works(?) at now y-combinator sponsored research into language design (not sure if he's active on hn though): http://www.tinlizzie.org/ometa-js/#Sample_Project http://www.tinlizzie.org/ometa-js/#Sample_Project Note, you need to select all before trying "do it"/"print it". See eg: the js compiler (top right, second drop down). I dare you to not find it so easy and fun that you don't try to implement a small DSL ;)