I always see Scheme books defining Scheme in terms of Scheme. SICP calls this a "metacircular evaluator". Why are these books unable to resist the temptation to write a Scheme interpreter using Scheme? Isn't it narcissistic?
Are the authors lazy and narcissistic, with the metacircular evaluators being a mirror of their own true selves?
This is the penultimate exercise in SICP:
Exercise 5.51: Develop a rudimentary implementation of Scheme in C (or some other low-level language of your choice) by translating the explicit-control evaluator of 5.4 into C. In order to run this code you will need to also provide appropriate storage-allocation routines and other run-time support.
As usual: "left to the reader as an exercise", "no answers provided".
Pure laziness.