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   Re: [xml-dev] XMap: A Mechanism for Mapping Names

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james anderson <james.anderson@setf.de> wrote:
| Arjun Ray wrote:

|> I'm sorry, I don't understand what you mean by "extent". 

| steele's book on common lisp contains a good dicsussion of scope and extent.
| (see http://www.cs.utsa.edu/research/AI/cltl/clm/node43.html#SECTION00700000000000000000)

Excellent reference, thank you.

I think the terms 'scope' and 'extent' in the sense of this reference are
inherently misleading when applied to markup.  There are no "variables" -
or "symbols" - to be "bound" (and then possibly "unbound"), a starttag is
not entry into a function call nor an endtag exit therefrom, and whether
constructs live indefinitely or die immediately, in whatever sense, is
defined by the application, if at all.  That is, I don't think trying to
coerce meaning into 'scope' and 'extent' in this context is useful.

If your concern is with how so called "namespace declarations" propagate
down an element hierarchy, then whatever problems there are with the
definition of such propagation would apply just as well to XMap usage.
This is because XMap can reproduce the *syntactic intent* of colonified
markup without loss of information.  Consider this example of starttag

 <foo:bar  foo:bar="foobar"  bar="foo">

In XMap, it could be written like this:

 <bar b1="foobar" bar="foo" xmlmap="foo fooey" fooey=":gi :gi bar b1">

That is, for any instance of colonified markup, equivalent XMap markup can
be devised mechanically.  The converse is not true in general, but if XMap
is *used* for namespacing as namespacing is practiced, then usage patterns
will be such that colonified markup equivalents of XMap markup can also be
computed.  That's all: it's just syntax.

(In fact, to be honest, I've been playing with XMap almost exclusively as
a new way to do AFs - the complete subsumption of colonification was a
freebie that fell out of the scheme, for reasons which were not hard to

If your concern is with the word 'map', which interpreted mathematically
could involve the notions of scope and extent, then perhaps 'translation'
in the linguistic sense could be a better word.  Just names and syntax.

|> I chose 'taxonomy', because it has connotations of an organizing scheme, 
|> over vocabulary, which suggests only a collection.
| please decide whether you want to describe operations over the elements 
| of "an organizing scheme, over [a] vovabulary" (regardless of what it 
| might suggest) or over the elements of a "name set".

This is instrumentality, not ontology.  An organizing scheme serves only
as a determinate source of names; that is, we know where all the relevant
names have come from.  This is a given, if not before the first left angle
bracket, then certainly by the time of the last right angle bracket.  Tag
markup consists of names associated with data values.  Unless the names
are made up on the spot, it is not unreasonable to assume that they are
drawn from somewhere.  XMap "operations" are on such names, as an author
would intend to use in a starttag: names drawn from disparate sources can
be "mixed" such that (a) more than one name can be associated with a data
item such as an attribute value, and (b) distinct attribute specifications
requiring the use of the same (lexical) name can be disambiguated.  There
is no implication of operations over elements of sets, or of functional
mappings other than the trivially one-shot circumstantial, per starttag.  

| please do it in advance.  please do not repeat the sins of "namespaces".

I have no idea what you're talking about.  Personally, I couldn't give a
flying <font> for "namespaces".  My concern is with colonification, which
I consider destructive.  XMap eliminates that syntactic device.  

|> The scope is the document.
| ?

I'm sorry, I believe I've used "scope" in a different sense from what you
were expecting.  Please ignore this statement - we'd just be talking past
each other. 

| can different elements in a given document map a given "local" name to
| different "external" names? your examples implied that this could be 
| permitted.


| which would imply at least "element" scope, rather than "document" scope. 

Perhaps the best way to accommodate your notion of scope would be talk in
terms of the markup in a starttag, because that's where the "operations"

| does the "element" scope entail contained elements?

I "guess" so, but then again, maybe not.  Seriously, I have no idea why
your notion of "scope" matters to you.


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