Another look at namespaces

James Tauber jtauber at
Mon Sep 20 10:46:08 BST 1999

> So we're having problems connecting the signifier 'language' to a meaning
> common across the participants of this list.

Indeed :-)

> The odd notion is of "formal grammars mapping to namespaces", not of
> "formal grammars", which range from useful to utterly useless.  Some of
> them are indeed odd, but it's not 'formal grammar' I'm questioning here.

Oh good.

> >These are all called "grammars". They all define things called
> >They are not "grammars" and "languages" the way Noah Webster used those
> >words or the way you seem to use them. They are "grammars" and
> >the way computer scientists use those words.
> Meaning one grammar + vocabulary -> language? Where the quantities are all
> one?

You don't actually need the "vocabulary". The alphabet of a formal language
is part of the grammar.

> I think in practice you may find multiple grammars used within the
> same language, even a formal one

Ahh. But now you are using "language" in a way other than "the set of
utterances generated by the grammar" right? Unless you mean that sometimes
the same syntactic rules can be expressed two different ways eg



a a*

> and (yuck for some) not just subsets (once you let ANY in the door, it all
goes).  Trying to keep it all
> exclusively singular seems to be a common dream throughout computing, but
> one I hope we can leave behind more and more over time.

Let me stress again, I am not saying you can always have a single grammar
for a particular "language". I am saying that you can have a single grammar
for a particular "formal language in the sense used by Paul".

> I think we might do well to ponder whether XML is really about creating
> formal languages or for encoding information already represented in
> languages.  If it's the latter, the results might be more interesting.

Why can't it be both? Isn't that the whole point of write schemata
(including DTDs)? Isn't it about formalising the encoding of this


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