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Subject: RE: [dita] Issue 12055 Map referencing behaviors
"Ogden, Jeff"
<jogden@ptc.com>
09/11/2007 12:58 PM |
|
"Ogden, Jeff"
<jogden@ptc.com>
09/10/2007 03:57 PM |
|
"Ogden, Jeff"
<jogden@ptc.com>
09/10/2007 03:05 PM |
|
My own thought here is that we have three options:
1. Define standard
behavior that applies to all cases, no exceptions.
2. Say that
the behavior is implementation dependent, possibly giving an example of
a desired behavior that may be implemented.
3. Provide
a standard behavior and a way to designate exceptions to that standard
behavior.
For this particular case I don’t think #3 would be too hard and so that
would seem to be a good way to go.
I am uncomfortable with the option that is being proposed which I take
as defining standard behavior, but allowing exceptions. The reason
I am uncomfortable with this is that it requires that someone who wants
to define a new specialization that requires exceptions provide both the
specialized elements and behavior. We have a standard way to provide
the specialized elements. We do not have a standard way to provide the
specialized behavior. Without a standard way to provide the specialized
behavior, someone will need to reimplement the specialized behavior for
different output processing implementations. That will be extra work and
seems likely to result in different results as documents are moved from
site to site and implementation to implementation. We should avoid that
if we can.
I could live with option #1 (no exceptions). That puts the burden
on the author to use the “right” map elements when the behavior they
want isn’t the standard behavior.
I could live with option #2 (no standard). That is what we do for
most output processing today.
And as I said, I think option #3 is the best approach. I think all
we need is either:
a) a
new attribute similar to domain on the root element of a map that accepts
a space separated list of topicref specializations whose behavior
should not be overridden when they are referenced using a different element
from a higher level map, or
b) a
new attribute similar to class on topicref and topicref specializations
that indicates that this element’s behavior should not be overridden when
referenced from a higher level map.
In either case, like domain or class, the new attribute would usually appear
with its default value in a DTD or schema and not in the instance.
And, if we want to, rather than using a simple list or a single attribute
value, we might define a keyword or grouping syntax for the values so that
we could use the same attributes for other similar purposes in the future
should the need arise. Some possible approaches:
Simple list on the root element: norefoverride=”element1
element2 … elementn”
Single valued attribute on the topicref
element or specialization: refoverride=”no”
Grouping syntax on the root element:
processing_exceptions=”norefoverride(element1
element2 … elementn) somenewoption(somenewvalues)”
Keyword list on any element: processing_exceptions=”norefoverride
somenewoption someothernewoption”
-Jeff
"Grosso, Paul"
<pgrosso@ptc.com>
09/10/2007 11:27 AM |
|
Robert,
If I understand correctly, you are suggesting that different
specializations can do different things based only on some
writeup in the standard.
Jeff and I have said that is the one choice we find unacceptable.
Either there needs to be some machine-readable way to determine
behavior (e.g., encode it in the DTD/XSDs), or all behavior must
be consistent. Having to hardwire potentially conflictly behavior
into an implementation for each specialization is not a good option.
Jeff and I will try to discuss this some more before tomorrow's
meeting, but I wanted to respond as soon as possible.
paul
> -----Original Message-----
> From: Robert D Anderson [mailto:robander@us.ibm.com]
> Sent: Monday, 2007 September 10 8:29
> To: dita@lists.oasis-open.org
> Subject: Re: [dita] Issue 12055 Map referencing behaviors
>
> Hi everybody,
>
> There is still no response to this one, so my plan for
> tomorrow's meeting
> is to keep to the original proposal. The specification should describe
> default behaviors for references from one map to another map,
> but allow
> that specializations may define alternate behaviors as appropriate.
> Compliant DITA processors should be expected to follow any alternate
> behaviors for OASIS approved elements, because those behaviors must
be
> described as part of the specification. However, there is no
> mechanism for
> processors to automatically determine the non-default
> behaviors for other
> specializations.
>
> I would be happy to have a way to define non-default behaviors for
map
> references. However, I am not sure how to come up with one
> that is simple
> enough to use, so it is not a part of this proposal.
>
> Thanks,
>
> Robert D Anderson
> IBM Authoring Tools Development
> Chief Architect, DITA Open Toolkit
> (507) 253-8787, T/L 553-8787 (Good Monday & Thursday)
>
> Robert D Anderson/Rochester/IBM@IBMUS wrote on 09/05/2007 04:28:03
PM:
>
> > In an attempt to draw out more responses on this one ...
> >
> > The issue under discussion is how to define differences in
> behaviors. To
> > make it easier, I will give a specific example.
> >
> > We have a chapter element defined in bookmap. When this
> points to a map,
> it
> > casts the referenced material in the role of a chapter, or
> a sequence of
> > chapters if there are multiple top-level elements. Attributes
and
> metadata
> > will cascade to the referenced 'chapters'.
> >
> > Within IBM we have another specialization, <topicsetref>.
> This is used to
> > point to commonly reused branches on a map. The behavior
> here differs -
> the
> > referenced material clearly is not cast into the role of a
> topicsetref.
> > Additionally, the topicsetref element defaults @type to
> 'topicset', which
> > indicates the type of the referenced target but should not
> be passed to
> the
> > targets. So, the map referencing behavior differs between
> chapter and
> > topicsetref.
> >
> > Because map is the most general DITA collection structure, it
should
> allow
> > appropriate processing based on the type of the collection
> and the type
> of
> > the collected content objects. That is, standard DITA map
> processing
> > behaviors are defaults appropriate to default DITA topics but
don't
> > preclude other processing behaviors.
> >
> > Options mentioned so far for defining this are:
> > 1) We specializers must expect to override programs to get anything
> > different from the default.
> > 2) We define overridable behaviors; programs may try to
> make it easier to
> > supply overrides to implement alternate behaviors
> > 3) Any behavior that differs from the default must be
> encoded in the DTD
> or
> > Schema (using a new, to-be-defined notation)
> > 4) OASIS approved elements that differ from the default
> must define the
> > difference in the specification. Default support for these
> differences
> > should be expected in processors, but simple support for
> differences in
> > user-created specializations is not guaranteed
> >
> > My own preference is for #1, because a) I think that
> differences from the
> > default should be expected, and b) I think defining those
> behaviors in
> the
> > DTD or Schema will be prohibitively complex. I would also
> be happy with
> #2,
> > although I do not think we can come up with a full list of
> overrides,
> just
> > like we cannot come up with a full list of specializations.
> If somebody
> can
> > suggest a DTD or Schema notation that is expandable and
> simple enough to
> > use for any case that might come up, I would readily shift
> my allegiance
> to
> > #3.
> >
> > Thanks -
> >
> >
> > Robert D Anderson
> > IBM Authoring Tools Development
> > Chief Architect, DITA Open Toolkit
> > (507) 253-8787, T/L 553-8787 (Good Monday & Thursday)
> >
> > Robert D Anderson/Rochester/IBM@IBMUS wrote on 08/30/2007
> 04:56:00 PM:
> >
> > >
> > > This is in reference to the proposal posted here:
> > >
> >
> http://www.oasis-open.org/committees/download.php/24910/IssueN
> umber12055.html
>
> >
> > >
> > > As noted at Tuesday's meeting, there has been some
> discussion off the
> > list
> > > about this item, primarily related to default behaviors.
> This proposal
> > > states that the described behaviors (such as that for cascading
> metadata)
> > > may change in a given specialization. For example, in the
general
> > topicref
> > > case and in most specializations, metadata specified within
the
> > <topicref>
> > > applies to the referenced content. This means that a
> processor could
> > treat
> > > specified metadata as if it was specified in the target
> topicref's.
> > >
> > > In some cases, the topicref element may be specialized to
provide
> meaning
> > > about the referencing context, rather than the target. In
> that case it
> > may
> > > be possible to set metadata that should not cascade to
> the targets, but
> > > should only be used to evaluate the reference itself.
> > >
> > > As I understand it, the open question is - how should
> such overrides of
> > the
> > > default behavior be defined? If they are not defined
> within the DTD or
> > > Schema, how can a tool anticipate the desired behavior?
> If they are
> > defined
> > > within the DTD or Schema, how can that be done, in a manner
that
> > > anticipates all of the overrides? If the changes are
> simply defined in
> > the
> > > element documentation, then tools will be unable to automatically
> > > understand how to treat the elements, and they will
> require overrides.
> > >
> > > Another, I believe less urgent, open question is about
> the terminology
> of
> > > cascading versus inheritance. It has been suggested that
> the behaviors
> > > described here, as well as in much of the map processing,
is more
> > properly
> > > described as cascading rather than inheriting. The
> proposal here uses
> the
> > > term "cascade". When this goes into the specification,
it
> will use the
> > same
> > > terminology as the spec, whether that ends up being
> cascade or inherit.
> > >
> > > Thanks -
> > >
> > > Robert D Anderson
> > > IBM Authoring Tools Development
> > > Chief Architect, DITA Open Toolkit
> > > (507) 253-8787, T/L 553-8787 (Good Monday & Thursday)
> > >
> >
>
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