Re: Weird XML rules

On Sat, 19 Mar 2022 at 13:45, Roger L Costello <[email protected]> wrote:

> On Thursday, Liam Quin wrote:
>
> > numeric character references are always treated as data when they are
> read, not markup.
>

Note that's true but  needs to be read with care as the same string may be
read twice (which is why the definition of &lt; requires double escaping).

<!DOCTYPE x [
<!ENTITY fooa "A &#60;b>x&#60;/b>">
<!ENTITY foob "B &lt;b>x&lt;/b>">
<!ENTITY fooc "C <b>x</b>">
]>
<x>&fooa; &foob; &fooc; </x>

foob using an entity reference &lt;  has replacement text using &lt; so
when foob is is referenced it generates the < as character data

 but for fooa, the numeric character reference &#60; produces the character
< in the replacement text of the entity fooa, so when that entity is used
the < starts a <b> start tag, so fooa is the same as fooc and produces a b
element.

$ rxp -x lt.xml
<x>A <b>x</b> B &lt;b&gt;x&lt;/b&gt; C <b>x</b> </x>