Not to put too much emphasis on this issue, which is decidedly minor, but converting json to a (compile-file friendly) s-exp representation should be fairly trivial, right? Again, minor detail. ;-)
i'm not sure i understand you Luis (especiall "compile-file friendly"), but it sounds like i should, because you're suggesting a solution that may be better.
are you saying that the json output could be converted to some sexp form with a macro on the top, so that the macro could expand into the cffi definitions? and this file should be the one that gets checked in to the repos, not the json file? (as opposed to generating a standalone tmp lisp file from the json file holding the cffi definitions in the ASDF fasl cache; which is done already)
cl-json itself reads it into alists, so it shouldn't be hard... but what would we gain? one slight drawback would be that M-. would take us to the big toplevel macro, not the actual cffi definition.
anything i'm not aware of?