                         (destructuring-bind (obj field) lhs
                           (let ((obj-sym (gensym)))
                             `(let ((,obj-sym (copy-alist ,obj)))
-                               (setcdr (assq ,field ,obj-sym) ,expr)
+                               (setcdr (assq ,field (cdr ,obj-sym)) ,expr)
                                ,obj-sym)))))))
     (+         . ,(lambda (token op) (psl--apply 'psl-+ (nth 1 op))))
     (-         . ,(lambda (token op) (psl--apply 'psl-- (nth 1 op))))


;; * Operators += and -= not yet implemented
;; * Equality tests are incomplete
;; * The empty object is currently (), so it evaluates to false
;; * Semicolon chaining not supported (outside of { } that is)
;; * At least a couple parser issues (max-lisp-eval-depth errors)
;; * A big pile of semantic issues that I don't know about yet

  "Implement ParselTongue's == function."
  (equal a b))

(defun psl-object-p (o)
  "Return t if argument is ParselTongue object."
  (and (listp o) (eq (car o) 'object)))

(defun psl-print (o)
  "Implement ParselTongue's print function."
  (cond
    ((eq o t)          (princ "true" t))
    ((null o)          (princ "false" t))
    ((functionp o)     (princ "function" t))
    ((psl-object-p o)  (princ "object" t))
    (t (princ o t)))
  o)

