xml-dev - Re: CharData and escaping ]]>

[Liam Quin <liamquin@interlog.com>]

Michael Kay at ICL wrote:
> If we assume that most XML will be software-generated, then it
> appears the only purpose of CDATA is to allow the software-writer
> to copy in a chunk of text without bothering to convert the <'s and
> &'s to &lt and &amp. But since he still has to check for any "]]>"
> in the text, and has no clear course of action if he finds one,
> it's not at all clear that it achieves this aim.

I'd say firstly that if you are writing software that works a character
at a time, it is generally easier to avoid CDATA marked sections and to
escape every < and & directly.  If you use a marked section, you need up
to 3 characters of lookahead, and you need to make sure that all of the
following sequences pass through unscathed:
    ]]]]]]]]]]]
    ]>
    a]b]]c]]]d

Secondly, the simplest way to escape ]]> is to insert a Unicode
zero-width non-printing non-combining space between the ] and the >.
This might be a pain for some applications, though.

> In practice I will just get round it by escaping all my >'s 
> as well as my <'s.

That's what I would do too.

Lee

-- 
Liam Quin --  the barefoot typographer -- Toronto
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