Re: [PATCH] xml-escape-region

[Daniel Colascione]

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On Oct 7, 2009, at 6:10 PM, Stefan Monnier wrote:

> > +;;;##autoload
> > +(defun xml-escape-region (beg end)
> > +  (interactive "*r")
> > +  (let ((escaped (xml-escape-string (buffer-substring beg end))))
> > +    (delete-region beg end)
> > +    (insert escaped)))
>
> I'd rather not autoload such a function.

Do you mean that it should be loaded all the time, or that the user  
should have to explicitly load xml.el before using the function? If  
the latter, then that would make binding it to a key less convenient.

>  But more importantly, this
> implementation is very inefficient.  xml-escape-string itself is  
> rather
> inefficient except for short strings; this is OK for its current uses,
> but for xml-escape-region it's definitely not good (i.e. only usable  
> for
> small regions).

How's this? It's O(N) in the amount of text escaped.

(defun xml-escape-region (beg end)
  "XML-escape text between BEG and END according to `xml-entity- 
alist`."
  (interactive "*r")

  (let ((search-re (mapconcat #'regexp-quote
                              (mapcar #'cdr xml-entity-alist)
                              "\\|"))
        (end (set-marker (make-marker) end)))

    (save-excursion
      (goto-char beg)
      (while (re-search-forward search-re end t)
        (replace-match (concat "&"
                               (car (rassoc (match-string 0)
                                            xml-entity-alist))
                               ";"))))))

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