Hi Tom,

This is a somewhat deprecated usage inherited from the SGML days.
I remember I used such machinery 10 years ago to have documents composed 
of text and binary contents. This had some sense since tools were 
supported it (I mean SGML/XML editors), but today, people tend to stick 
media to their documents à la HTML, with a simple href attribute.

Tom Anderson a écrit :
> 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
> 


-- 
Cordialement,

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|      Philippe Poulard       |
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