I like this. The focus on lexing/parsing for language implementation often overshadows the fact that the bulk of the work in any language effort is in the semantics and analysis (e.g., everything after one has a parse tree). On the production compiler I get paid to work on, front end work makes up at most 10% of the team time and effort. Even on experimental language projects that we occasionally play with, the front end is usually given minimal attention - just enough to have a syntax that we can use to start instantiating ASTs and doing the interesting work. More often than not, I punt on a front end altogether and just piggyback on some existing language (e.g., Haskell, ML, etc) and basically explore the semantics or analysis questions I'm interested in via a DSL-style embedding and ignore syntax altogether.