[New-ITS] namespace abbreviations

[Grahame Grieve]

well, there's some suppliers / xml people on this list.

I will assume that fixing the namespace prefix is a
historical left over from early xml days, and not relevant
in today's standards.

unless we hear otherwise....

Grahame


Charlie McCay wrote:
> Grahame
> 
> Using multiple namespaces is a pain in XSLT if the same structure exists
> in different namespaces -- thus if structures derived from a common
> model all were in different namespaces then writing namespace-agnostic
> templates to do common processing is not nice.  Same goes (only more so)
> for using namespaces to manage versions -- stylesheets written to use
> one namespace would need to be changed to work with another.
> 
> Early versions of the HL7v3 XML ITS  used a different namespace for each
> messagetype - which made for clean type names but ugly instances and
> made code reuse (certainly in XSLT) more difficult.
> 
> I agree that we should avoid using more than one namespace. 
> 
> 
> Fixing the prefix would not make much difference to XSLT -- the prefixes
> in the templates do not need to be the same as the prefixes in the
> instance, the XSLT processor dereferences them and uses the namespace
> URI for matching.  One can set the prefix to be used for a namespace in
> XSLT output, so that is ok too.  However other tools may not be so
> flexible -- and the name clash issue remains.
> 
> There was an argument in the past that it was worth fixing prefixes
> because it made DTD validation possible -- that may be why it has got
> into some standards.  There has been no demand for DTD support in the
> HL7 community for a while
> 
> I agree that it would be interesting to get supplier views on this  
> 
> All the best
> 
> Charlie
> 
> 
> Charlie McCay, charlie at RamseySystems.co.uk Ramsey Systems Ltd, 23D
> Dogpole, Shrewsbury, Shropshire SY1 1ES
> 
> tel 01743 232278 / 07808 570172  skype: charliemccay
> 
> 
>   
> 
>> -----Original Message-----
>> From: Grahame Grieve [mailto:grahameg at gmail.com] On Behalf Of 
>> Grahame Grieve
>> Sent: 31 July 2006 11:52
>> To: Charlie McCay
>> Cc: grahame at jivamedical.com; new-its at lists.hl7.org.uk
>> Subject: Re: [New-ITS] namespace abbreviations
>>
>>
>> We certainly want to try not to use multiple name spaces.
>>
>> I think it just means that xslt processing is a lot easier - 
>> doesn't xslt have problems with namespaces?
>> how do the existing suppliers xslt interfaces handle this?
>>
>> For the reasons you say, I was surprised to see it done, but 
>> these are widely used standards that do it.
>>
>> Grahame
>>
>>
>> Charlie McCay wrote:
>>> Grahame
>>>
>>> This is foreign to me too -- I have seen it as style guidance for 
>>> hand-authored schemas -- and that is reasonable -- but unless there 
>>> are other interoperability standards that are fixing prefixes in 
>>> instances I think that we should avoid it.
>>>
>>> Even if there are we should tread carefully -- HL7v3 
>> fragments will be 
>>> included with XML fragments from many other namespaces -- 
>> and if the 
>>> habit of fixing namespace prefixes spreads there will be 
>> name clashes 
>>> that cannot be sorted.  Thus while we may think that no one 
>> else will 
>>> want the prefix "hl7", it is unreasonable to expect this to be a 
>>> normal way to process XML fragments - and so may well 
>> restrict the use 
>>> of some tools etc.
>>>
>>> If we go for more than one namespace (such as a namespace for every 
>>> model), then we will use up prefixes far faster, and the 
>> case against 
>>> fixed prefixes gets even stronger (as the likelihood of 
>> direct clashes
>>> increases)
>>>
>>> All the best
>>>
>>> Charlie
>>>
>>>    
>>>
>>>
>>> Charlie McCay, charlie at RamseySystems.co.uk Ramsey Systems Ltd, 23D 
>>> Dogpole, Shrewsbury, Shropshire SY1 1ES
>>>
>>> tel 01743 232278 / 07808 570172  skype: charliemccay
>>>
>>>
>>>   
>>>
>>>> -----Original Message-----
>>>> From: new-its-bounces at lists.hl7.org.uk 
>>>> [mailto:new-its-bounces at lists.hl7.org.uk] On Behalf Of 
>> Grahame Grieve
>>>> Sent: 20 July 2006 06:27
>>>> To: new-its at lists.hl7.org.uk
>>>> Subject: [New-ITS] namespace abbreviations
>>>>
>>>> Would any one like to comment on the idea that the standard should 
>>>> fix the namespace abbreviations used in the instances?
>>>>
>>>> Several of the NDR's I have read do this, but it is foreign to my 
>>>> thinking.
>>>>
>>>> Grahame
>>>> _______________________________________________
>>>> New-ITS mailing list
>>>> New-ITS at lists.hl7.org.uk
>>>> http://lists.hl7.org.uk/mailman/listinfo/new-its
>>>>
>>>>
>> --
>> Grahame Grieve
>> CTO, Jiva Medical       Software Integration Tools
>> CTO, Kestral Computing  Healthcare Applications
>>
>>
> 

-- 
Grahame Grieve
CTO, Jiva Medical       Software Integration Tools
CTO, Kestral Computing  Healthcare Applications