[DDI-users] DDI 3.2: optional xml:lang attribute in StringType
Wendy Thomas
wlt at umn.edu
Wed Dec 10 10:40:25 EST 2014
Thanks, we'll add this to our documentation edits.
Wendy
On Wed, Dec 10, 2014 at 9:32 AM, Jani Hautamäki <Jani.Hautamaki at staff.uta.fi
> wrote:
> Thanks for clarifying this.
>
> It might be a good idea to amend the field-level specification
> for InternationalStringType with something like this:
>
> The value for the attribute xml:lang must always be defined
> either implicitly or explicitly.
> If the attribute is not explicitly set,
> its value is inherited from the parent.
> Consequently, there can be only one <r:String> child
> without xml:lang set explicitly within an InternationalStringType element.
>
> --
>
> The inheritance of information (eg. xml:lang) from parent creates
> some issues with respect to the XML linearisation process
> (the process of converting the hierarchical DDIInstances into
> flat list of Fragments). These issues are solvable though.
>
> An example follows.
>
> First, there is the minimalistic ddi:DDIInstance with
> id "ddi_instance". The @xml:lang is defined in the root element.
>
> ddi_instance.xml
> ------8<------8<------
> <?xml version="1.0" encoding="utf-8"?>
> <ddi:DDIInstance
> xmlns:ddi="ddi:instance:3_2"
> xmlns:r="ddi:reusable:3_2"
> xmlns:s="ddi:studyunit:3_2"
> xml:lang="fi"
> >
>
> <r:Agency>acme.org</r:Agency>
> <r:ID>ddi_instance</r:ID>
> <r:Version>1</r:Version>
>
> <s:StudyUnit>
> <r:Agency>acme.org</r:Agency>
> <r:ID>study_unit</r:ID>
> <r:Version>1</r:Version>
>
> <r:Citation>
> <r:Title>
> <r:String>otsikko suomeksi</r:String>
> </r:Title>
> </r:Citation>
>
> </s:StudyUnit>
> </ddi:DDIInstance>
> ------8<------8<------
>
> The <r:String> element does not have the attribute @xml:lang explicitly
> set. However, the root element has @xml:lang explicitly set to "en",
> and therefore the <s:StudyUnit>'s title has the @xml:lang implicitly
> set to "en" too.
>
> Because the <s:StudyUnit> is inherited from r:AbstractMaintainableType,
> it is possible to maintain it as an independent object.
>
> As an independent object the <s:StudyUnit> does not have @xml:lang
> defined for any of its children. Moreover, assuming a default @xml:lang
> value "en_us" for the <s:StudyUnit> would lead to a contradiction.
>
> This problem becames more apparent, when the above ddi:DDIInstance
> is linearised into flat list of ddi:Fragments, and then the StudyUnit's
> Fragment is reused in another DDIInstance.
>
> Here's the linearised version of the above document,
>
> fragments1.xml
> ------8<------8<------
> <?xml version="1.0" encoding="utf-8"?>
> <ddi:FragmentInstance
> xmlns:ddi="ddi:instance:3_2"
> xmlns:r="ddi:reusable:3_2"
> xmlns:s="ddi:studyunit:3_2"
> >
>
> <ddi:Fragment>
> <ddi:DDIInstance xml:lang="fi">
>
> <r:Agency>acme.org</r:Agency>
> <r:ID>ddi_instance</r:ID>
> <r:Version>1</r:Version>
>
> <r:StudyUnitReference>
> <r:Agency>acme.org</r:Agency>
> <r:ID>study_unit</r:ID>
> <r:Version>1</r:Version>
> <r:TypeOfObject>StudyUnit</r:TypeOfObject>
> </r:StudyUnitReference>
> </ddi:DDIInstance>
> </ddi:Fragment>
>
> <ddi:Fragment>
> <s:StudyUnit>
>
> <r:Agency>acme.org</r:Agency>
> <r:ID>study_unit</r:ID>
> <r:Version>1</r:Version>
>
> <r:Citation>
> <r:Title>
> <r:String>otsikko suomeksi</r:String>
> </r:Title>
> </r:Citation>
> </s:StudyUnit>
> </ddi:Fragment>
>
> </ddi:FragmentInstance>
> ------8<------8<------
>
> Now, consider another FragmentInstance, which reuses the StudyUnit
> from the previous FragmentInstance
>
> fragments2.xml
> ------8<------8<------
> <?xml version="1.0" encoding="utf-8"?>
> <ddi:FragmentInstance
> xmlns:ddi="ddi:instance:3_2"
> xmlns:r="ddi:reusable:3_2"
> xmlns:s="ddi:studyunit:3_2"
> >
>
> <ddi:Fragment>
> <ddi:DDIInstance xml:lang="en">
>
> <r:Agency>acme.org</r:Agency>
> <r:ID>another_ddi_instance</r:ID>
> <r:Version>1</r:Version>
>
> <r:StudyUnitReference>
> <r:Agency>acme.org</r:Agency>
> <r:ID>study_unit</r:ID>
> <r:Version>1</r:Version>
> <r:TypeOfObject>StudyUnit</r:TypeOfObject>
> </r:StudyUnitReference>
> </ddi:DDIInstance>
> </ddi:Fragment>
>
> </ddi:FragmentInstance>
> ------8<------8<------
>
> This DDIInstance is identified as "another_ddi_instance",
> and it differs from the previous "ddi_instance" only by setting
> a different value for the xml:lang.
>
> Given these two FragmentInstances, "fragments1.xml" and "fragments2.xml",
> is is possible to reconstruct (or "delinearise") two different
> DDIInstances.
> One is equal to the first XML document, "ddi_instance.xml",
> and the other DDIInstance is shown below,
>
> another_ddi_instance.xml
> ------8<------8<------
> <?xml version="1.0" encoding="utf-8"?>
> <ddi:DDIInstance
> xmlns:ddi="ddi:instance:3_2"
> xmlns:r="ddi:reusable:3_2"
> xmlns:s="ddi:studyunit:3_2"
> xml:lang="en"
> >
>
> <r:Agency>acme.org</r:Agency>
> <r:ID>another_ddi_instance</r:ID>
> <r:Version>1</r:Version>
>
> <s:StudyUnit>
> <r:Agency>acme.org</r:Agency>
> <r:ID>study_unit</r:ID>
> <r:Version>1</r:Version>
>
> <r:Citation>
> <r:Title>
> <r:String>otsikko suomeksi</r:String>
> </r:Title>
> </r:Citation>
>
> </s:StudyUnit>
> </ddi:DDIInstance>
> ------8<------8<------
>
> When "ddi_instance.xml" and "another_ddi_instance.xml" are compared,
> they both contain literally identical manifestation of the StudyUnit
> identified as "acme.org:study_unit:1".
>
> However, the StudyUnit's @xml:lang is implicitly set, and its
> value depends on which DDIInstance is being used. This leads
> to an ambiguous definition of the Maintainable in question.
>
> Obviously, this is undesirable.
>
> The Title of the StudyUnit "acme.org:study_unit:1" should have
> the language defined independently of the containing DDIInstance.
>
> The resolution to this problem is obvious though, but has a notable
> impact on the linearisation/delinearisation process.
>
> When doing a linearisation (DDIInstance->FragmentInstance) each inherited
> attribute must be explicitly set on each Maintainable before
> the Maintainables are dismantled into Fragments.
>
> Conversely, after a Maintainable has been delinearised
> (FragmentInstance->DDIInstance), the redundant xml:lang attributes
> should be cleaned up to reduce noise.
>
> This approach implies that an XML document must be considered
> equivalent to itself when the inherited values are explictly set.
>
> The question is then:
> Is the following document equivalent to the first one with
> respect to the DDI-Lifecycle 3.2 specification,
> as required by my approach?
>
> The original document "ddi_instance.xml" is transformed so
> that each xml:lang attribute has its value explicitly set,
> and the XML document should no longer rely on inheritance in any place.
>
> ddi_intance.noinheritance.xml
> ------8<------8<------
> <?xml version="1.0" encoding="utf-8"?>
> <ddi:DDIInstance
> xmlns:ddi="ddi:instance:3_2"
> xmlns:r="ddi:reusable:3_2"
> xmlns:s="ddi:studyunit:3_2"
> xml:lang="fi"
> >
>
> <r:Agency>acme.org</r:Agency>
> <r:ID>ddi_instance</r:ID>
> <r:Version>1</r:Version>
>
> <s:StudyUnit xml:lang="fi">
> <r:Agency>acme.org</r:Agency>
> <r:ID>study_unit</r:ID>
> <r:Version>1</r:Version>
>
> <r:Citation>
> <r:Title>
> <r:String xml:lang="fi">otsikko suomeksi</r:String>
> </r:Title>
> </r:Citation>
>
> </s:StudyUnit>
> </ddi:DDIInstance>
> ------8<------8<------
>
>
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>
>
--
Wendy L. Thomas Phone: +1 612.624.4389
Data Access Core Director Fax: +1 612.626.8375
Minnesota Population Center Email: wlt at umn.edu
University of Minnesota
50 Willey Hall
225 19th Avenue South
Minneapolis, MN 55455
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