Common Lisp does not have any built-ins for declaring static local variables known e.g. from C. int test_function() { static int counter = 0; r

Common Lisp does not have any built-ins for declaring static local variables known e.g. from C. int test_function() { static int counter = 0; return counter++; } test_function(); // -> 0 test_function(); // -> 1 test_function(); // -> 2 So, well, we can just implement them ourselves. It's Lisp, after all! (defun test-function () (static-let ((counter 0)) (incf counter))) (test-function) ; -> 1 (test-function) ; -> 2 (test-function) ; -> 3 This article is done in a literate programming style, attempting both to teach the basics of Lisp writing style and to describe the details of this static binding implementation.