anchor.diff:  
   (defun make-tm-region (begin end
                          &key
  -                       begin-captures end-captures
  +                       begin-captures end-captures captures
                          name content-name (patterns (make-tm-patterns)))
     (make-instance 'tm-region
                    :begin (ppcre:create-scanner begin)
  
positive.code:                         (if (find-tree :back-reference end)
                              end
                              (ppcre:create-scanner end)))
                   :begin-captures begin-captures
                   :end-captures end-captures
                   :name name
                   :content-name content-name
                   :patterns patterns))
  
negative.code:                  (line-add-property (point-line point) start1 (tm-result-end end-result)
                                      :attribute (tm-rule-name rule)
                                      nil)
                   (tm-apply-begin-captures rule point begin-result start-line-p)
                   (tm-apply-end-captures rule point end-result)
                   (tm-apply-content-name rule point start1 (tm-result-start end-result) nil)
                   (set-syntax-context (point-line point) nil)
                   (line-offset point 0 (tm-result-end end-result))
  