Its interesting that despite the utility of S-Expressions, as mentioned, semantic diff, for example, of CL code is uncommon.

By that I mean highlighting the diff between these:

  (dolist (i l)
    (print (car i)))

  (dolist (i l) (print (cdr i)))

With the diff highlighting the `car` changed to `cdr` rather than just the raw lines being changed.

I'm pretty sure this exists, but it's uncommon (at least to me its uncommon).