15:20:43nij-Being buildable only in themselves: " Allegro Common Lisp2, LispWorks2, CMUCL, Scieneer CL2, Clozure CL;" page 4 of https://research.gold.ac.uk/id/eprint/2336/1/sbcl.pdf
15:21:36beachProbably because they haven't found another way.
15:22:08beachSome of those are not built from source as Krystof points out.
15:22:53beachThey are modified by running the system, loading new code, and then dumping the memory contents.
15:24:04nij-I thought this wasn't possible (in order not to be flaky) because redefining bindings in package CL is undefined?
15:24:07beachIt was a major thing that the SBCL people wanted done differently from CMUCL, and it was not easy.
15:24:38beach*sigh* it is undefined by the standard, but not by any particular implementation.
15:24:58beachnij-: You need to distinguish between the language and its implementations.
15:25:02bikeif you're only running on your own system, it will only be flaky if you let it be flaky
15:25:34nij-Oh! That's why doing it in their own implementation is easier!
15:25:51beachThat's why doing it in their own implementation is the only possibility.
15:26:16beachTheir implementations are not written to be loaded into any other implementation.