now my language workbench patches up load-history properly! it also passes data for how to load each sublanguage’s functions to the JIT native compiler, so JIT now seems to work in all cases as expected
next up, defining advice for the backend functions that eldoc and helpful use so that the emacs documentation system can read from non-elisp files
this whole thing has involved surprisingly little advice which is satisfying. there’s a minor mode that reversibly establishes a couple of bits like the language workbench’s entry in magic-mode-alist, which parses files for a #lang line and sets the major mode from that