I wrote a Lisp in F# last year, and I started with Fexprs and used them as the basis to write quasiquote and defmacro, which are then used to write things like

I wrote a Lisp in F# last year, and I started with Fexprs and used them as the basis to write quasiquote and defmacro, which are then used to write things like defun and let: "backtick char ` is expanded to quasiquote by the reader" (defmacro! quasiquote (flambda (form) (_qq-expand form))) (defmacro! define-macro (flambda (sig :rest body) `(defmacro! ~(car sig) (flambda ~(cdr sig) ~@body)) )) (define-macro (defun name vars :rest forms) `(def! ~name (lambda ~vars ~@forms)) (define-macro (lisp/let bindings :rest forms) `( (lambda ~(map first bindings) ~@forms) ~@(map second bindings) )) (define-macro (let :rest forms) (if (contains? forms :in) `(~'clj/let ~@forms) `(~'lisp/let ~(car forms) ~@(cdr forms)) )) There is a certain amount of brain-warping required understanding it all, and getting the nested quasi- and regular- quotes right takes some getting used to, even for me going back and trying to grok it -- but it's bootstrapping code, so once your primitives are defined, you can move on.