The thing is, it wasn't used for developing and debugging the demo code. In the Lisp world, there exist small interpreters whose only job is to boostrap implem

The thing is, it wasn't used for developing and debugging the demo code. In the Lisp world, there exist small interpreters whose only job is to boostrap implementations. They are not used for developing any of the code they run; it is assumed to be correct. Handling of conditions that don't occur can be left out. Definitely, this has its place.