Multi level embedding of xml files

[campbell.shaun]

The application I am writing uses XML files for validation. I've been
able to set up my xml files so that I can share validation for common
fields using external entities. eg

<?xml version="1.0"?>
<!DOCTYPE foo [
<!ENTITY ch1 SYSTEM "http://www.wiz.org/project/chap1.xml">
<!ENTITY ch2 SYSTEM "http://www.wiz.org/project/chap2.xml">
<!ENTITY ch3 SYSTEM "http://www.wiz.org/project/chap3.xml">

]>

<foo>
.... document instance here ...
</foo>

....
<foo>

<BLIVET>&ch1;</BLIVET>

<BLIVET>&ch2;</BLIVET>

<BLIVET>&ch3;</BLIVET>

</foo>

This works fine but I would like to extend it so that I can include
smaller chunks of xml in the included xml file. The problem I have is
with the DOCTYPE declaration in the sub xml file which I need to
include the sub-sub xml file as I don't want this included in my top
level document.

Is it possible to do what I want to do?

Regards

Shaun

 

[Richard Tobin]

This works fine but I would like to extend it so that I can include
smaller chunks of xml in the included xml file. The problem I have is
with the DOCTYPE declaration in the sub xml file which I need to
include the sub-sub xml file as I don't want this included in my top
level document.

Is it possible to do what I want to do?

No, external entities are not complete XML files and can't have DTDs.
You will have to define the entities in the top level file. You could
modularize the top-level DTD using parameter entities in the same way
as you have modularized the document itself: put the small chunk
entity definitions in separate files like "chap1.dtd", and include
them as external parameter entities in the top-level DTD like this:

<!DOCTYPE foo [
<!ENTITY ch1 SYSTEM "http://www.wiz.org/project/chap1.xml">
<!ENTITY % ch1-ents SYSTEM "http://www.wiz.org/project/chap1.dtd">
%ch1-ents;
<!ENTITY ch2 SYSTEM "http://www.wiz.org/project/chap2.xml">
<!ENTITY % ch2-ents SYSTEM "http://www.wiz.org/project/chap2.dtd">
%ch2-ents;
....

Each of chap1.dtd, chap2.dtd, ... could use more parameter entities to
cut it into even smaller chunks.

-- Richard

 

[Richard Tobin]

I forgot to say:

<!ENTITY ch1 SYSTEM "http://www.wiz.org/project/chap1.xml">
<!ENTITY % ch1-ents SYSTEM "http://www.wiz.org/project/chap1.dtd">
%ch1-ents;

You could put the definition of ch1 itself in chap1.dtd too.

-- Richard