| Re: Identification in the XML list files and its references [message #1141 is a reply to message #1138] |
Mon, 10 December 2012 16:49   |
Dirk Bräuer
Messages: 313
Registered: August 2008
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Senior Member |
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Dear Susanne and all others,
> The separate XML list files should be an easier to maintain replacement
> for schema-internal enumeration lists.
+1
I think it is a compromise between a free string and an XML enumeration
type.
> * Should a railML file be meaningful without this list file?
>
> That would mean to refer to the /meaningful/ 'code' value, that is not
> unique.
Between the contradictory aspects of "uniqueness" and "easy to read at
text file level", I would prefer a technical uniqueness in case of
doubt. This means: Rather refer to /id/ than to /code/ in favour of
consequence.
If anybody wants to create an "easy to read" XML file he may use a
meaningful /id/ for test purposes.
> * Should a railML file be meaningful only with knowledge of the list
> file, only in cases, where its attributes are used?
>
> That would mean to refer to the _unique_ but not /meaningful/ 'id'
> value.
Again the same answer from my side.
> * Should both possibilities be provided? If the list file is present, it
> may be looked up for further details, if not, the value is
> /meaningful/ anyway.
>
> That would mean to refer to both values.
> <designator register="RL100" registerRef="registers.xml#d1e51" entry="..."/>
As we have already agreed to avoid redundancies as far as possible, this
should not be an option. What should a reading software do if there are
to contradictory references at one element? I. e. an <ocp> refers to a
<register> using a /registerRef/ but the attribute /register/ of the
<ocp> is different than the appropriate attribute in the additional XML
file?
I think RailML is more a technical data exchange format than a text
format for intuitive reading. So, the readability has to step back in
cases of doubt. There is still the possibility to create "easy readable"
files using meaningful /id/s. This possibility is good, but it should be
the left to explicit test cases. For all-day work, interoperability
should be the main aim.
With best regards,
Dirk.
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