---
Test
---
Shows the usage of a static variable.
''"Let Over Lambda Over Let Over Lambda"''

| script | lisp interpreter fixture |
| show   | evaluate text | !-

(let ((direction 'up))
  (defun toggle-counter-direction ()
    (setq direction
          (if (eq direction 'up)
            'down
            'up)))

(defun counter-class ()
    (let ((counter 0))
      (lambda ()
        (if (eq direction 'up)
          (setq counter (+ counter 1))
          (setq counter (- counter 1)))))))
                                                           -!|
| show   | evaluate text | (setq my-counter (counter-class)) |
| check  | evaluate text | (funcall my-counter)              | 1 |
| check  | evaluate text | (funcall my-counter)              | 2 |
| check  | evaluate text | (funcall my-counter)              | 3 |
| show   | evaluate text | (toggle-counter-direction)        |
| check  | evaluate text | (funcall my-counter)              | 2 |
| check  | evaluate text | (funcall my-counter)              | 1 |
| check  | evaluate text | (funcall my-counter)              | 0 |
| show   | evaluate text | (toggle-counter-direction)        |
| check  | evaluate text | (funcall my-counter)              | 1 |
| check  | evaluate text | (funcall my-counter)              | 2 |
| check  | evaluate text | (funcall my-counter)              | 3 |