A couple of months ago, I wrote about Christopher Neufeld’s series on the less familiar parts of Common Lisp. He’s up to the Fs now so if you’re interested in Lisp, you should check in with his latest posts.
One recent post concerns the fboundp function. You might think that there’s not much to cover. After all, a symbol is either bound to a function or not. But it turns out that there’s some edge cases and Neufeld uses those explore how
(mapcar #'some-function some-list)
and
(mapcar 'some-function some-list)
differ. If you’re like me, the second case is a bit of a surprise. Forms like that are common in Emacs Lisp but, one would think, non-sensible in Common Lisp.
It turns out, though, that sometimes a form like that does make sense and the results can indeed be different from the first. See Neufeld’s post for the details.