what is cd in (cd *db*)?

In Practical Common Lisp there's a code that helps display a list in a much cleaner form

(defun dump-db ()
  (dolist (cd *db*)
    (format t "~{~a:~10t~a~%~}~%" cd)))

The syntax for dolist is described as
dolist (var list-form [result-form]) declaration* {tag | statement}*
but I i can't quite figure out what cd is in (cd *db*)

could someone help me crack this one?

That would be great!!

Thanks,
-m

(dolist (cd *db*)
dolist (var list-form [result-form])

In the syntax descriptions in CLHS top level parentheses are omitted and [] denotes optional component. This is modified Backus-Naur Form. Knowing this you should be able to figure out what "cd" corresponds to.

Hint: that's not the only place you see that symbol. Look at how it's used elsewhere in the function, and it should start to make sense.
The documentation should also help.

(dolist (a '(1 2 3 4))
   --body--code--)

Could be rewritten as

(destructuring-bind (a . rest) '(1 2 3 4)
   (tagbody :start 
      --body--code--
      (setf a (car rest) rest (cdr rest))
      (when rest (goto :start))))

If that helps.

dolist (var list-form [result-form]) declaration* {tag | statement}*

Cd is the var and *db* is the list-form, and the optional result-form is not used. There can be any number of declaration; there are none. There can be any number of tag or statement; there are no tags and the only statement is (format t ...).

I second Rmarren's suggestion to take a look at BNF.

Roughly: "For every album in the database, print it like this."

Historical note: when PCL was published CDs were a common physical medium for distributing albums