(defmacro are (expectations form &optional description &rest format-args)
  `(eval-in-context
    *context*
    (make-instance 'comparison-result
                   :expression '(are ,expectations ,form)
                   :value-form ',form
                   :body (lambda () (multiple-value-list ,form))
                   :expected ',(mapcar #'second expectations)
                   :comparison (lambda (a b)
                                 (and ,@(mapcar (lambda (expectation)
                                                  (list (first expectation) `(pop a) `(pop b)))
                                                expectations)))
                   ,@(when description
                       `(:description (format nil ,description ,@format-args))))))