[btilly]

If you're interested, The Structure and Interpretation of Computer Programming winds up writing a Scheme interpreter in Scheme.

This is part of a proud and surprisingly long-standing tradition. The first Lisp interpreter was originally written in Lisp by one person, and then hand translated into assembly by another. This came as a surprise to the rest of the lab who had intended to work on an actual implementation in a year or two. You know, some time after they came up with a real syntax for it.