Inheritance and other buzzwords

Peter Murray-Rust peter at
Fri Apr 3 11:45:01 BST 1998

At 15:20 02/04/98 -0800, Tim Bray wrote:

[...An analysis I agree with...]

If readers feel that namespaces are all doom-and-gloom, let me say that I
am very happy indeed with the present namespace proposal. It adds precisely
2 major features - the uniquification of names and the identification of
those names. 
Two years ago I was struggling with early versions of CML. I had called my
generic variable VAR (reasonable?). I think had the blinding revelation
that chemistry involved text as well as molecules. Write my own DTD for
this? No - re-use the HTML DTD. Only problem, HTML also has a VAR. I asked
the SGML community and was more-or-less told that SGML was broken in this
respect. In the next version of CML I therefore created variables CML.MOL
and XML.VAR (sic - I created something called eXperimental Markup Language,
before the current XML).

So the current namespace proposal gives me exactly what I wanted, and also
gives me the confidence and authority to use it.

CML:MOL will work for 99% of the applications I shall be involved in. I
have no problem about (say):
	<HTML:P>This is a molecule</HTML:P>
<!-- gory molecular details omitted -->

[I *would* have had a problem with context-sensitive minimisation...]

My problem only comes when I encounter the Concrete Materials Laboratory
who also use CML as their prefix. If I want to mix existing document from
CML and CML I have to edit one set. Tedious. But we do this sort of thing
every day for other reasons (how many of you have run automatic edits
through documents when companies' names change, etc.). No big deal.

So I am very excited about the formal opportunity to have interoperable
chemistry documents.

[To put this in context - before XML (i.e. 1997) we use fortran-based data
files. These often have no spaces between fields (some of you may never
have seen a fortran file, but they really are like that.). But your
airplanes are built on fortran - no dynamic memory allocation, 6-letter
variables, implicit typing - etc. Namespaces are a bit like the fortran of
XML. There is a huge amount you can do with them - often tedious, but you
can do it. A major advance on machine-code programming.]


>In fact, why doesn't someone on this list write such a preprocessor?  I 
>think conventional DTD's, with the additional leverage of universal names, 
>would be damn useful.

Seconded. I suspect that a few simple utilities will help a great deal. For
example a filter to rename prefixes in a document (though I expect sed
would be adequate).


Peter Murray-Rust, Director Virtual School of Molecular Sciences, domestic
net connection
VSMS, Virtual Hyperglossary

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