Re: [vwrap] What abstract type systems already exist?

Dzonatas Sol <> Mon, 09 May 2011 23:06 UTC

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Date: Mon, 09 May 2011 15:57:48 -0700
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Subject: Re: [vwrap] What abstract type systems already exist?
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On 05/09/2011 01:36 PM, Boroondas Gupte wrote:
> *What abstract type systems do currently exist *("exist" as in 
> published and sufficiently documented. Don't have to be formally 
> standardized, though if they are, that's a plus.)* and how do they 
> compare to LLSD?*

We know Meadhbh wants DSD and we obviously can avoid DTD in every 
message. I see the main pivot that Meadhbh wants is less symbology, yet 
that still means a solution for others. I'm thinking something like the 
XML2RFC editor has an ideal solution, but I'm scientist, so it's not my 
pen to determine that way.

However, let's look at DTD:

> For each such ATS, it'd be useful to know:
>     * How flexible is it?
>       (Could it be used for VWRAP? For that, its set of types probably
>       must already be designed for general purpose or (like LLSD) with
>       typical virtual world data in mind.)

It's very flexible, however people often don't know how to implement 
optimizations properly. They usually just present the end result, like 
LLSD. Consider something like SVG/XHTML, and there should be no 
complaints of what is possible. We could express this more in terms of 
ontology with WebGL and likewise and maybe the ideal more clique-in.

>     * Is it extensible? How does the extension mechanism work?

If some definition doesn't work, then we could put XSL+DTD into the 
works to transform and extend.

>    *
>     * Are there serializations defined for it? If so, which ones?

Serialize XML data?  Easy, just remove the tags. I don't know why people 
consider XML as THE serialized data. XML just helps format the data.

>     * How entangled is the ATS itself with the serializations?

I think people use XML the wrong way and abuse it. When people add 
attributes to XML tags not for flow issues, then that usually is a sign 
of XML abuse.

>     * How simple is it? (Both conceptually and for implementors of
>       (de)serializers etc.)

Consider the example:
<?xml version="1.0"?>
<!DOCTYPE note [
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT heading (#PCDATA)>
<body>Don't forget me this weekend</body>

When serialized looks like this:

Don't forget me this weekend


The reader only needs to apply the DTD to deserialize back into XML.

There are differences between "strict" DTD and non-strict.  Strict typed 
allow dynamic placement of data such the DTD only has to specify the 
types once. The reader parsers the data and translates them into types. 
That level of transmission and optimization should be negotiable, however.

Why is this WG concerned with reinventing ASCII?  For those that don't 
know we could say that means Abstracted Serialized Codex 
Internationational Interchange, yet we still deal with backword 
compatibility to double nybble types (DNT).

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