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Re: FPIs

From: <lee@sq.com>
Date: Wed, 27 Nov 96 17:33:42 EST
Message-Id: <9611272233.AA03218@sqrex.sq.com>
To: w3c-sgml-wg@w3.org

Debbie wrote:
> A URL is all on the front end.  An FPI is 
> by definition NOT on the front end and guarantees indirection.
> Are we trying to forbid indirection and force front-endedness?
> Is that the objection?

You can get client-side indirection in some areas with
    <!Entity server "http://www.softquad.com/sgml">

    <A HREF="&server;/teip3.dtd">
and this does not require further extension.

Unfortunately, & and % are not recognised in SGML system identifiers,...
   [they're system data, defined as character data, which in turn is
    defined as data character*, where data character is defined as SGML
    character, which in turn is defined as (why would anyone want to
    simplify SGML??) markup character | DATACHAR, where markup character
    is name character, function character or DELIMCHAR, where name character
    is name start character | Digit | LCMNMCHAR | UCNMCHAR, and a .... aaargh!
    But at any rate it turns out that entities aren't expanded in them.
   ]
Therefore you can't use this technique for the DTD or for entity sets
included in the DTD.

None the less, you can do something just like an SGML open catalog in XML
right now today:

<?stuff?>
<!DOCTYPE BOY [
    <!Entity catalog SYSTEM "catalog.sgml">
    <!--* Catalog is used to override locations of public texts *--> 
    %Catalog;
    
    <!Entity Latin1 SYSTEM "entity-sets/iso-latin1.sgml">
    %Latin1;
    
]> <BOY>.....</BOY>  

Now put the real URL for Latin1, if you need to override it, in
catalog.sgml, and you have the indirection that Murray Altheim mentioned.

Panorama lets the local copy of the SGML OPEN CATALOG file override the
copy on the remote server (assuming the documents are on a remote server),
and the mechanism I have described does not address that.

Power Users may have to wait for XML 2.

Lee
Received on Wednesday, 27 November 1996 17:34:04 EST

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