A package riddle (19 Aug 2009)

The other day, I spent some time debugging a surprising issue in Lisp code written for CoCreate Modeling. Turns out that the problem can be shrunk down to only a few lines, and is actually quite instructive on how Lisp's packages work - an ideal candidate for this blog!

So here is the innocent-looking code:

(defun test()
  (test_dialog))

(in-package :clausbrod.de)
(use-package :oli)

(sd-defdialog 'test_dialog
  :ok-action '(display "test_dialog"))

Copy/paste this code into a file called test.lsp, then load the file into a fresh instance of CoCreate Modeling. Run the test function by entering (test) in the user input line. Can you guess what happens now? Can you explain it?

To be continued...

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