Re: Nested entity declarations in DTDs

its the same behavior with XercesJ, with following findings.

The original XML document instance, produces following error,

[Fatal Error] test.xml:23:4: The parameter entity reference "%a;" cannot
occur within markup in the internal subset of the DTD.

But doing like following,

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE feed SYSTEM "nest1.dtd">
<feed xmlns="&a;">&b;</feed>

Parses without issues.

On Sun, Mar 13, 2022 at 9:57 PM David Carlisle <[email protected]>
wrote:

> You can have the definitions but you can't reference them as you can't
> have parameter entity references in the internal subset, rxp moans:
>
> $ rxp -sx nes1.xml
> Error: PE ref not allowed here in internal subset
>  in entity "g" defined at line 19 char 1 of file:///c:/tmp/nes1.xml
>  in unnamed entity at line 23 char 4 of file:///c:/tmp/nes1.xml
>
>
>
> If on the other hand you do this in an external DTD it is fine
>
> <?xml version="1.0" encoding="utf-8"?>
> <!DOCTYPE feed SYSTEM "nest1.dtd">
>
> <feed xmlns="&a;">&b;</feed>
>
> where nest1.dtd is
>
> <!ENTITY a 'http://www.w3.org/2005/Atom'>
> <!ENTITY b '&e;&f;&g;&h;&i;'>
> <!ENTITY c 'tag:xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/'>
> <!ENTITY d 'http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/'>
> <!ENTITY e '<title>Obfuscated Atom</title>
>   <updated>2007-10-19T00:00:00+00:00</updated>
>   <id>&c;</id><link rel="alternate" href="&d;"/>
>   <link rel="self" href="&d;1_4.atom"/>
>   <author><name>James Holderness</name></author>'>
> <!ENTITY % a '<entry><title>This is title #'>
> <!ENTITY % b '</title><updated>2007-10-18T23:'>
> <!ENTITY % c ':00+00:00</updated><id>&c;'>
> <!ENTITY % d '</id><link href="&d;'>
> <!ENTITY % e '.html"/><summary type="html">
>   This is the <code>summary</code> for entry number '>
> <!ENTITY % f '.</summary></entry>'>
> <!ENTITY % g '<!ENTITY f
> "&#37;a;1&#37;b;59&#37;c;1&#37;d;1&#37;e;1&#37;f;">'>
> <!ENTITY % h '<!ENTITY g
> "&#37;a;2&#37;b;58&#37;c;2&#37;d;2&#37;e;2&#37;f;">'>
> <!ENTITY % i '<!ENTITY h
> "&#37;a;3&#37;b;57&#37;c;3&#37;d;3&#37;e;3&#37;f;">'>
> <!ENTITY % j '<!ENTITY i
> "&#37;a;4&#37;b;56&#37;c;4&#37;d;4&#37;e;4&#37;f;">'>
> %g;%h;%i;%j;
>
>
> produces:
>
>
>
> $ rxp -x nes1.xml
> <feed xmlns="http://www.w3.org/2005/Atom"><title>Obfuscated
> Atom</title>&#10;  <updated>2007-10-19T00:00:00+00:00</updated>&#10;
>  <id>tag:xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/</id><link
> href="http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/"
> rel="alternate"></link>&#10;  <link href="
> http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/1_4.atom"
> rel="self"></link>&#10;  <author><name>James
> Holderness</name></author><entry><title>This is title
> #1</title><updated>2007-10-18T23:59:00+00:00</updated><id>tag:
> xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/1</id><link href="
> http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/1.html"></link><summary
> type="html">&#10;  This is the <code>summary</code> for entry number
> 1.</summary></entry><entry><title>This is title
> #2</title><updated>2007-10-18T23:58:00+00:00</updated><id>tag:
> xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/2</id><link href="
> http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/2.html"></link><summary
> type="html">&#10;  This is the <code>summary</code> for entry number
> 2.</summary></entry><entry><title>This is title
> #3</title><updated>2007-10-18T23:57:00+00:00</updated><id>tag:
> xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/3</id><link href="
> http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/3.html"></link><summary
> type="html">&#10;  This is the <code>summary</code> for entry number
> 3.</summary></entry><entry><title>This is title
> #4</title><updated>2007-10-18T23:56:00+00:00</updated><id>tag:
> xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/4</id><link href="
> http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/4.html"></link><summary
> type="html">&#10;  This is the <code>summary</code> for entry number
> 4.</summary></entry></feed>
>
> On Sun, 13 Mar 2022 at 15:40, <[email protected]> wrote:
>
>> Hello all,
>>
>> I was wondering if anyone could help clarify an aspect of the
>> specification for DTDs; I am currently working on an XML parser, but have
>> never really used DTDs myself.
>>
>> http://www.詹姆斯.com/blog/2007/10/obfuscated-atom
>> <http://www.xn--8ws00zhy3a.com/blog/2007/10/obfuscated-atom>
>>
>> In the above URL, there is a DTD (copied below) with nested entity
>> declarations, is this valid?
>>
>> <?xml version="1.0" encoding="utf-8"?>
>> <!DOCTYPE feed [
>> <!ENTITY a 'http://www.w3.org/2005/Atom'>
>> <!ENTITY b '&e;&f;&g;&h;&i;'>
>> <!ENTITY c 'tag:xn--8ws00zhy3a.com,2006-05-04:/tests/atom/obfuscated/'>
>> <!ENTITY d 'http://www.xn--8ws00zhy3a.com/tests/atom/obfuscated/'>
>> <!ENTITY e '<title>Obfuscated Atom</title>
>>   <updated>2007-10-19T00:00:00+00:00</updated>
>>   <id>&c;</id><link rel="alternate" href="&d;"/>
>>   <link rel="self" href="&d;1_4.atom"/>
>>   <author><name>James Holderness</name></author>'>
>> <!ENTITY % a '<entry><title>This is title #'>
>> <!ENTITY % b '</title><updated>2007-10-18T23:'>
>> <!ENTITY % c ':00+00:00</updated><id>&c;'>
>> <!ENTITY % d '</id><link href="&d;'>
>> <!ENTITY % e '.html"/><summary type="html">
>>   This is the <code>summary</code> for entry number '>
>> <!ENTITY % f '.</summary></entry>'>
>> <!ENTITY % g '<!ENTITY f "&#37;a;1&#37;b;59&#37;c;1&#37;d;1&#37;e;1&#37;f;">'>
>> <!ENTITY % h '<!ENTITY g "&#37;a;2&#37;b;58&#37;c;2&#37;d;2&#37;e;2&#37;f;">'>
>> <!ENTITY % i '<!ENTITY h "&#37;a;3&#37;b;57&#37;c;3&#37;d;3&#37;e;3&#37;f;">'>
>> <!ENTITY % j '<!ENTITY i "&#37;a;4&#37;b;56&#37;c;4&#37;d;4&#37;e;4&#37;f;">'>
>> %g;%h;%i;%j;
>> ]>
>> <feed xmlns="&a;">&b;</feed>
>>
>>
>>
>> Saxon and the XSLT processor in Chrome both say no, but if you try the
>> processor in Firefox it appears to process fine.
>>
>> http://xsltfiddle.liberty-development.net/jy6KM8g
>>
>> Any pointers in the right direction would be appreciated, many thanks in
>> advance. :)
>>
>

-- 
Regards,
Mukul Gandhi