I suppose it depends on your definition of "native". Scheme and Lisp are designed to be extensible, so adding memoization is as simple as including a few lines

I suppose it depends on your definition of "native". Scheme and Lisp are designed to be extensible, so adding memoization is as simple as including a few lines of macro definitions. e.g., see the block of text commented as "The Memoization facility" in this file: http://norvig.com/paip/auxfns.lisp http://norvig.com/paip/auxfns.lisp