Hi all,

I can see from the XML spec what processing instructions and notations 
are, syntactically. I even just about understand how notations relate to 
external entities. But i don't understand what you'd actually use them for 
in practice!

The one example i've found is using an xml-stylesheet PI to specify a 
stylesheet. Are there others?

How about notations and external entities? Is the idea that they're a 
mechanism of linkage to external files that's more concrete than just 
using a URL? So, if i was writing a bizarro world HTML, i could specify 
images like this in the DTD:

<!NOTATION jpeg SYSTEM "http://some-kind-of-URL">
<!NOTATION png SYSTEM "http://some-other-kind-of-URL">
<!ELEMENT img EMPTY>
<!ATTLIST img
 	src ENTITY
 	alt CDATA #IMPLIED >

Then in my document i could write:

<!DOCTYPE img PUBLIC "-//Bizarro HTML" "http://bizarrohtml" [
  <!ENTITY lena SYSTEM "lena.jpg" NDATA jpg>
]>
<img src="lena" alt="picture of Lena"/>

?

Can i also use that entity in regular text, like:

<p>Here is a picture of Lena &lena;</p>

?

And in both cases, what does it *mean*? If i parsed that into DOM and 
called getAttribute("src") on the img element, what would i get back?

What's the point of being able to declare an attribute as being of type 
NOTATION?

And does anyone actually use any of this stuff?

tom

-- 
I'm angry, but not Milk and Cheese angry. -- Mike Froggatt