Re: [xml-dev] XML vocabulary for expressing constraints?

[Steve Newcomb <srn@coolheads.com>]

On 12/13/2013 11:11 AM, davep wrote:
> On 13/12/13 14:46, Steve Newcomb wrote:
>> Unambiguous non-interactive communication is hard to do.
> 
> Are you taking two extremes Steve?
> If you (initially) take a mid ground and deal in what you say it isn't
> it seems doable.
>   It's an image of X
>   It's a text document describing Y
>   It's a video showing Z
> 
> I'm less interested in the stream of bytes, more in what it is
> representing.
> 
> Your abstract idea of the constitution is .. harder, too abstract for XML?
> 
> Is it this abstract idea you were getting at?

I was only trying to demonstrate that the href value's semantic is
extremely ambiguous, unless and until there's sufficient context, shared
by the author/sender with the user/recipient, to make it unambiguous, or
at least to restrict its ambiguity.

When people speak sincerely, they generally intend to be speaking about
specific things, and they *believe* that those things are what they are
talking about.  In a dialogue, it's possible to detect and resolve
misunderstandings and confusions.  In a non-interactive context -- one
that doesn't involve a reverse channel from the recipient to the sender
-- it's much harder for either end of the channel to be sure of anything.

Now that you've shared some context with me, you have reduced the
ambiguity of the references you will make in future HTML-like messages
from you to me.  From now on, I'll know that when you utter an href,
you're more likely *not* to be doing so because you want to talk about a
data stream, and more likely to be talking about something *represented*
by it.  That helps, perhaps, but it tends to eliminate only one among a
very large number of interpretive options still available to me.
Usually, I'm going to need more guidance in order to be confident that I
know the meaning you're intending to convey.

No, I don't think it's too abstract for XML, any more than it's too
abstract for English.  Both English and XML can be used to convey
thoughts about abstractions.  In my own work, I often see XML used to
express kind-of and instance-of relationships, and, yes, to attach
thoughts to those relationships.

Indeed, some such semantics are built into XML itself: it has element
types and element instances, for example.  The latter kind of
relationship is a pretty abstract thing, but the only reason it's hard
to talk about is that XML lacks a rhetoric for talking about it.

Digression: It could have such a rhetoric inherently, but I think would
be the wrong way to go about it; it would be a one-off solution to a
much more general problem, one that would leave the general problem, er,
unaddressed.  Anyway, in all my years of working with this stuff, I've
never had an occasion to talk about the *relationship* between a
specific element type and a specific instance of that element type.

Nevertheless, it should be possible to talk about such a relationship,
and to do so unambiguously. Question: What would make that possible?
Answer: A way to establish a context for references to such
relationships -- a context in which the necessary rhetorical facilities
exist.  And then, of course, one would actually use those facilities.

Note that I do NOT claim that that's easy or simple in any sense.  I
estimate that it's just about as hard as living with others in peace and
prosperity.  In fact, I suspect the two problems are closely related.