words (RE: extensibility in XSchema?)

[W. Eliot Kimber]

At 11:16 PM 6/22/98, Peter Murray-Rust wrote:

>You and I are tackling different problems, I think. I *think* I understand
>what AFs are for - it allows you to identify one (or more) elements and
>their relation to one (or more) other elements. IOW when your document is
>mapped onto a meta-DTD is says - FOO in doc maps to BAR in the meta-DTD.
>Since we 'know' what BAR means, we have now associated its meaning with FOO.

Close, but not the whole picture.  Before you get to the individual
elements, an architecture simply says "this set of rules, however defined,
governs this document".

Given the statement you can then, separately say "for my purposes,
documents governed by this set of rules should be processed by the program
'x'".

You then provide some way to associate the *name* for the architecture
(that is, it's public ID as specified by the 'public-id' attribute in the
architecture use declaration) with the program, which you might do with
MIME mapping (say using the architecture name or some such--I'm not
conversant with the details of MIME).

Thus, I don't think this statement:

>What I am asking for is different. I 'know' what <FOO> is. I simply want to
>map it onto a program. NOT a piece of prose. The program will define the
>semantics/behaviour of the element. 

Is really true.  Or rather, you can get where you want from the information
provided by the architecture use declaration.

>>2. A way to get the parts of that definition in some predictable ways.
>
>Don't understand this.

What I hear you saying is:

Part of the definition of the semantics of this thing is a program that
does something useful.  I want that part of the defintion.

Thus, you want to get part of the total definition that we presume exists
*and* the getting of it needs to be sufficiently standardized that either
existing Web infrastructure provides it or it wouldn't be too hard to get
the Web infrastructure providers to provide it.  Thus your use of MIME.

>(b) set a mapping in mailcap as:
>	chemical/x-pdb: /usr/bin/rasmol

I suspect this is the key--what is "mailcap"? Is it something local to your
system? If so, then it is functionally identical to this

-- SGML open mapping catalog --
PUBLIC "+//IDN me.com//NOTATION Foo Architecture//EN"
       "/usr/bin/rasmol"

And then configuring your XML processor to run the program as a result of
resolving the mapping.  

This is pretty much what I do in PHyLIS (www.phylis.com) for associating
notations with grove constructors and grove renderers with property sets
(you might construct several groves, each with its own schema, from the
same entity, so processing must be in terms of the property set that
governs a grove, not the notation that defines the data from which the
grove was constructed). 

If mailcap is not local, how do you add to it?

Cheers,

E.
--
<Address HyTime=bibloc>
W. Eliot Kimber, Senior Consulting SGML Engineer
ISOGEN International Corp.
2200 N. Lamar St., Suite 230, Dallas, TX 95202.  214.953.0004
www.isogen.com
</Address>

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