I'm new to scheme (my lisp experience limited to configuring emacs) and I'm trying to better understand recursion and conses. I'd like to get debugging output, showing each call to a function, so I can better visualize the recursion.
Noodling around, I came up with
(define (last lst)
(if (null? (cdr lst))
(car lst)
(last (cdr lst))))
to get the last member of a list. It seems to work. To debug this, I came up with
(define (last lst)
(print "Debug: " lst)
(if (null? (cdr lst))
(car lst)
(last (cdr lst))))
which for (last '(a b c d)) results in
Debug: (a b c d)
Debug: (b c d)
Debug: (c d)
Debug: (d)
In CHICKEN, is there a more idiomatic way to get debugging output on each call to the function, so I can see how the calls to the function progress?
Nope, that's basically how I do it too. If you want something more convenient, you could try the trace egg which can automatically give you call nesting and input parameters.
If you want to get a bit fancier, you could use the "Feathers" debugger which comes shipped with CHICKEN.