harlan

ly be represented as such. Of course, there is also an alternative style, which may be preferable if you have debugging tools for designing your compiler passes at least equivalent to the Lisp macro expansion debugging. You can simply write your entire DSL compiler as a single function, and then wrap it into a macro, as `(defmacro mydsl (&rest args) (mydsl-compiler args))`. This way, the same compiler infrastructure can be reused for an interpreted or partially interpreted version of your DSL, if you need it. Still, all the same rules apply to how the passes are implemented in that compiler function. Another very useful trick is to make your DSLs composable, which is easy if you split your compilation pipeline into separate macro expansion passes. Multiple DSLs may easily share features of their internal IRs or even front-end languages, so any new DSL would simply cherry-pick features from a number of existing DSLs and wrap them into a simple front-end. This degree of composability is simply impossible with the function-based interpreted eDSLs. A can recommend taking a look at the Nanopass [1] framework, which is built around this very ideology, or at my own DSL construction framework [2]. [1] http://andykeep.com/pubs/np-preprint.pdf And some examples: https://github.com/cisco/ChezScheme https://github.com/eholk/harlan [2] https://github.com/combinatorylogic/mbase