[topicmapmail] CTM Use Cases

[Alexander Johannesen]

On 11/10/05, Dipl.-Wirtsch.-Inf. Lutz Maicher
> Unfortunately, however, this doesn't work, because the second part of
> the qname (after the colon) has to begin with a letter. So for numeric
> identifiers this doesn't work. :-(  [cited from a email from Lars Marius]

Well, there are a few issues somewhat related. Your problem ;

>  #PREFIX isbn @"urn:isbn:"
>  [isbn:0201749602 : bibtex:BOOK =3D "XML Topic Maps: ..."]

This creates the id of "urn:isbn:0201749602", unless I've
misinterpreted something vital here (and hence ignore the rest of this
mail :). The LTM spec says for ID it requires 'qname', which is
defined as ;

   qname      ::=3D NAME ':' NAME | NAME

and NAME as ;

   NAME       =3D [A-Za-z_][-A-Za-z_0-9.]*

As far as I can tell, using an URN already fixes your problem as the
URN isn't interpreted as such (and hence don't need to follow the
<NSS> requirement from RFC2141), but as a string.

> Is this not that useful syntactical constraint relaxed in the requirement=
s
> of CTM?

That depends on what you mean by 'not that useful' ; for me who work a
*lot* in XML and want to adhere to the standard, keeping the
identifiers to the XML Name specification is a great help, as I can
use many formats without conversions.

IIRC, this is done to simplify things because of the XML ID attribute
used in XTM ;

  [4]  NameChar ::=3D Letter | Digit | '.' | '-' | '_' | ':' |
CombiningChar | Extender
  [5]  Name  ::=3D (Letter | '_' | ':') (NameChar)*

  http://www.w3.org/TR/REC-xml/#NT-Names

There isn't anything in TM itself that should have this constraint as
long as *XTM* id attributes are XML Name compliant, but I guess it
makes it easier for us all to do it this way.

And if it still is a problem, why 'isbn:12345' using prefixes? Why not
just use literal 'isbn-12345'? (Unless you're doing crazy things like
attaching ID semantics of the topic to the ID attribute! :)


Alex
--
"Ultimately, all things are known because you want to believe you know."
                                                         - Frank Herbert
__ http://shelter.nu/ __________________________________________________