• "Inherit" refers to the type hierarchy. A specialized element inherits base processing.
• "Cascade" refers to the navigation hierarchy (or any other containment hierarchy). A property on a <topicref> cascades to contained <topicref> elements.

• The <templateref> parent is a specialized <topicref> that refers to an HTML page that's a template with placeholder fields for lists of topics. The parent defaults the format attribute to "html" and the type attribute to "template" so processes can recognize the template.
• The <fieldref> children are specialized <topicref> elements that identify the placeholder fields and default the toc attribute to "no" so the TOC processing skips the fields. This element certainly shouldn't pick up any cascades from higher in the navigation hierarchy.
• The grandchildren are ordinary <topicref> elements providing the topic references for listing in the field. They certainly shouldn't pick up the defaulted format or type attributes from the <templateref>, and it's arguable (given that they aren't really part of the navigation hierarchy) that they shouldn't pick up any cascades.

• Control cascades for specified or all properties to a node.
• Control cascades for specified or all properties through a node to contained nodes.

Michael Priestley <mpriestl@ca.ibm.com> 09/11/2007 04:43 PM

To "Ogden, Jeff" <jogden@ptc.com> cc dita@lists.oasis-open.org Subject RE: [dita] Issue 12055 Map referencing behaviors

"Ogden, Jeff" <jogden@ptc.com> 09/11/2007 06:34 PM

To Michael Priestley/Toronto/IBM@IBMCA cc <dita@lists.oasis-open.org> Subject RE: [dita] Issue 12055 Map referencing behaviors

"Ogden, Jeff" <jogden@ptc.com> 09/11/2007 02:56 PM

To <dita@lists.oasis-open.org> cc Subject RE: [dita] Issue 12055 Map referencing behaviors

Actually I’d be happy with no flexibility and no new architectural attribute. With that approach the referencing map would always override the referenced map. But this makes it hard for me to come up with concrete scenario’s that require flexibility.

I think Robert has cases where specializers don’t want the referencing map context to override the referenced map context. And he thinks Erik has some more complicated cases where simple inherit or not options aren’t enough. This leads to the desire to allow exceptions and to give specializers some flexibility.

So what we might do is have Robert or Erik provide the concrete case(s). I’d be happy to plug those cases into the output processing pipeline implementation and architectural attributes that I described in my previous note.

-Jeff

"Ogden, Jeff" <jogden@ptc.com> 09/11/2007 12:58 PM

To <dita@lists.oasis-open.org> cc Subject RE: [dita] Issue 12055 Map referencing behaviors

It is true that the specializers would need to add information for a new architectural attribute to their new DTDs or schemas if they want to override the default behavior, but are developing new DTDs or schemas anyway so this does not seem like a bad thing or a large burden.

If we put the new architectural attribute on individual elements rather than on the root element (more class-like rather than domain-like), doesn’t most of the need to manage the attributes through generalization and conref processing go away? Typically we’d just use the default value, if any, from the DTD or schema for the current element (generalized or not). If for some reason the architectural attribute is stored in the document instance, if you have access to the DTD you’d just get the new value for the “new” element during generalization and store that in the instance, or if you don’t have access to the DTD or schema, you could simply delete the architectural attribute from the instance and fallback to the default behavior.

I guess my desire to add the additional information to the DTD or schema comes from my desire to make the map to map referencing behaviors more of a requirement of the DITA Standard and less of an optional set of behaviors that is left fairly open and handled by output processing. Perhaps this is a mistake on my part, but I think of the map to map referencing behavior as being somewhat more complicated than most styling issues (ph as bold or not) that are handled by output processing entirely or largely outside of anything in the DITA Standard. The map to map referencing behavior seems somewhat similar to the portions of the DITA spec. that talk about “Metadata elements and common attributes” in that the information in one document is interacting with and possibly overriding information in another. For the metadata case at least the behavior isn’t optional, but something that is required by the DITA Standard (things in maps can override things in topics). I’ve been thinking about the map to map referencing behavior in a similar way. And adding a new architectural attribute allows us to give specializers some flexibility while still saying exactly what the behavior is in the standard.

Here is an example. Imagine an output processing pipeline that:
1. reads and resolves information from various maps,
2. gathers and “transforms” dita topics referenced from the maps, combining and splitting topics, adding related-links, metadata and other contextual information including map to map referencing context to the resulting topics or collections of topics,
3. processes the “transformed” topics for styling issues, and
4. produces the desired final output.

The map to map referencing behaviors would likely be implemented in steps 1 and 2 (probably mostly step 2). Styling issues would be dealt with in step 3 or possibly step 3 and 4. Steps 3 and 4 may never see information from a map directly. Any reasonable output processing system will make it fairly easy for someone to customize/style their documents in step 3. It may be much more difficult or even impossible to add specialization specific customizations to step 2. If we can include information about map referencing behavior in the DTD or schema in some fashion, we can provide flexibility in step 2 without requiring specializers to implement their own specialization specific customization in step 2. And if this flexibility is provided as part of the standard, there would be less work for specializers to do to actually use it.

The alternative is to leave the map to map behavior up to output processing with a suggestion in the DITA spec. that suggests how this should work by default. I could live with this approach, but for the reasons I stated earlier I’d rather see this be defined as a requirement. If we do leave the map to map referencing behavior up to output processing, we should make sure our descriptions in the DITA spec. make that clear and we should probably work to make the map to map description shorter as Robert suggested in an earlier message.

So far I’m still thinking that the new architectural attribute here could be pretty simple (inherit or not), but I look forward to seeing some more cases from Erik Hennum or others.

-Jeff

"Ogden, Jeff" <jogden@ptc.com> 09/10/2007 03:57 PM

To Michael Priestley/Toronto/IBM@IBMCA cc <dita@lists.oasis-open.org>, "Grosso, Paul" <pgrosso@ptc.com> Subject RE: [dita] Issue 12055 Map referencing behaviors

OK, but for those cases where “the DITA Open Toolkit provides specialized behaviors for about a third of the specialized elements in the DITA spec” do the specialized behaviors provided override something that is required in the DITA standard or do they override the processing for the base element as implemented by the DITA Open Toolkit?

I see the “Specialization in processing” section of the DITA specification as a collection of good practices for writing XSLT or CSS stylesheets for use with DITA. I don’t think it defines a standard method of sharing processing behaviors unless the sharing is being done using the same processing system such as the DITA Open Toolkit.

The DITA Open Toolkit, like all output processing systems, implements portions of the DITA standard as well as other things that have not been standardized and very often we do not want to standardize. I guess a question we may need to answer is, Are the behaviors being defined in Issue 12055 ones that we want to include in the DITA Standard or are they ones that we want left open for customization? And if we include them in the DITA Standard, how much force do we want to give them? Are they requirements? Are they recommendations? Are they examples?

Michael, do you see any harm in providing additional information in the DTD or schema as I have been suggesting (my option #3)?

-Jeff

"Ogden, Jeff" <jogden@ptc.com> 09/10/2007 03:05 PM

To Michael Priestley/Toronto/IBM@IBMCA, "Grosso, Paul" <pgrosso@ptc.com> cc <dita@lists.oasis-open.org> Subject RE: [dita] Issue 12055 Map referencing behaviors

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

To <dita@lists.oasis-open.org> cc Subject RE: [dita] Issue 12055 Map referencing behaviors

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)
> > >
> >
>

• Follow-Ups:
  • RE: [dita] Issue 12055 Map referencing behaviors
    • From: "Ogden, Jeff" <jogden@ptc.com>

• References:
  • RE: [dita] Issue 12055 Map referencing behaviors
    • From: Michael Priestley <mpriestl@ca.ibm.com>

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