> as a learning exercise to become more intimately familiar with lambda calculus and s-expressions Any Scheme implementation will be better for this. Much less

> as a learning exercise to become more intimately familiar with lambda calculus and s-expressions Any Scheme implementation will be better for this. Much less primitives, one namespace for everything, hygienic macros, immutablity by default/encouraged. CL is exactly the opposite of that - it's complicated because it wants to be practical. And for the most part it is. It supports procedural, functional and OO programming, probably logic programming too with the right library. It's designed as a real system for solving real problems - and as such is not the best tool for learning about lambda calculus. Actually you could program imperatively in CL for the long time before ever feeling awkward. Scheme, with it's mandatory TCO and encouraged immutability is much better for learning lambda calculus... and about Lisp in general.