# Re: URN: wrapper

JWilliams.SBD-E@rx.xerox.com
Thu, 21 Oct 1993 03:30:59 PDT

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    Date: 	Thu, 21 Oct 1993 03:30:59 PDT

    From: JWilliams.SBD-E@rx.xerox.com

    Subject: Re: URN: wrapper

    To: uri@bunyip.com

    Message-Id: <"21-Oct-93 11:30:59 +1".*.John_G._Williams.sbd-e@rx.Xerox.com>

are we not confusing the syntax of the URN which is one thing, with how that
thing is encapsulated in a particular document format (or application)?

How you encapsulate data into a document format should consider what works well
with the encoding structures, conventions and software that apply to this
format. Thus you get different answers for different formats.

If the discusion on angle brackets is just centred on ascii let me crawl back
under my stone. If not, I suggest we are going astray.

examples:
<URN:ISSN:....> for ascii.
<urn>URN:....</urn> for sgml
-- for ASN.1 based applications
urn ATTRIBUTE WITH
ATTRIBUTE-SYNTAX caseIgnoreString -- case sensitivity is an open issue
SINGLE VALUE
::= urn-att-id

These examples show different encapsulations of the same string value. They
also hightlight a redundancy in that both the SGML and ASN.1 examples already
tag the encapsulated data, and dont require an additional tag within the value.

a) adapting the wrapper to suit the application seems the way of addressing
both the concerns of the SGML folk, ascii, and etc...., in a sane and
straightforward way.

b) you can eliminate the redundancy if you view the tagging as the
responsibility of the encapsulation rather than the URN itself:
<URN:ISSN:....> for ascii.
<urn>ISSN:....</urn> for sgml

where the components "<URN:" and ">" are viewed as part of the encapsulation
into ascii, not an inherent part of the URN value.

Either way, every value I have shown comes with a tag. All this shows is that
if you want to tag something, the tag can just as easily be provided by the
encapsulation. As yet it is not clear to me why we need the tag to be an
inherent part of any UR* value.

-- Jock Williams --

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