title: How much lisp to implement in C before writing extension in itself?
body: <p>I am implementing a lisp interpreter in C, i have implemented along with few primitives like cons , car, cdr , eq, basic arithmetic stuff.</p>
  
  <p>Just before i was starting to implement define and lambda it occurred to me that i need to implement an environment. I am unsure if i could implement it in lisp itself.</p>
  
  <p>My intent is to implement minimal amount of lisp so that i could write extension to the language in itself. I am not sure how much is minimal, Would implementing FFI Qualify as minimal ?</p>