Well, what that really means is that Lisp can handle its own code as smoothly as it can data, since the two take the same form. The reverse can also be true, t

Well, what that really means is that Lisp can handle its own code as smoothly as it can data, since the two take the same form. The reverse can also be true, though; data "is" code, in that if you design a data structure sufficiently well, for example, the necessary code to work with it should be self-evident. (Interestingly, "data is code" is probably more characteristic of Forth and (in a very different way) the relational paradigm.)