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OPML+RDF/XTM?

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  • Danny Ayers
    Has anyone played with Outline Processor Markup Language (OPML) [1] alongside RDF or Topic Maps? Not thought this through much but I would imagine there could
    Message 1 of 9 , Mar 31, 2002
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      Has anyone played with Outline Processor Markup Language (OPML) [1]
      alongside RDF or Topic Maps? Not thought this through much but I would
      imagine there could be a lot of potential, not least for an RDF or XTM
      editor, where you might have an outline view (backed by OPML) with pluggable
      semantics (from XTM or RDFS).

      Cheers,
      Danny.

      [1] http://www.opml.org

      ---
      Danny Ayers
      <stuff> http://www.isacat.net </stuff>
    • christopher_ogden
      I ve thought about combining OPML with RDF and XTM, because RDF and XTM are not well suited for hierarchical content, like OPML is. But it doesn t seem very
      Message 2 of 9 , Apr 5, 2002
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        I've thought about combining OPML with RDF and XTM, because RDF and
        XTM are not well suited for hierarchical content, like OPML is. But
        it doesn't seem very feasible to connect OPML with RDF and XTM until
        OPML (or its de facto successors) puts content into an element,
        rather than into an attribute, like the rest of the XML world.

        If OPML were more orthodox, you could have RDF, XTM, and even SVG
        graphics as a node element of an "OPML 2.0" outline. And I don't
        think any RDF, XTM, or other XML tools, including browsers, would be
        willing to implement an OPML outline as an element, or xlink to an
        OPML node, until OPML comes within the XML fold.



        --- In opml-dev@y..., "Danny Ayers" <danny666@v...> wrote:
        > Has anyone played with Outline Processor Markup Language (OPML) [1]
        > alongside RDF or Topic Maps? Not thought this through much but I
        would
        > imagine there could be a lot of potential, not least for an RDF or
        XTM
        > editor, where you might have an outline view (backed by OPML) with
        pluggable
        > semantics (from XTM or RDFS).
        >
        > Cheers,
        > Danny.
        >
        > [1] http://www.opml.org
        >
        > ---
        > Danny Ayers
        > <stuff> http://www.isacat.net </stuff>
      • Danny Ayers
        hmm - I must admit having a literal text as an attribute does seem a little unorthodox. However I m not convinced the choices made are really an obstacle to
        Message 3 of 9 , Apr 5, 2002
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          hmm - I must admit having a literal 'text' as an attribute does seem a
          little unorthodox. However I'm not convinced the choices made are really an
          obstacle to including metadata. The <head> element could contain
          document-wide metadata in exactly the same fashion as HTML, and individual
          items could also be described like :


          <outline text="Heart of Glass.mp3" type="song" f="Blondie - Heart of
          Glass.mp3">
          <metadata>
          ... dc:creator="Debbie Harry" ...
          </metadata>
          </outline>

          or whatever. Minor changes to the DTD.

          I've not played with XTM, but you're certainly right about RDF - it can get
          a bit clunky when describing simple hierarchies. But the fact is that it
          can, whereas OPML can't describe arbitrary graph data (well, not without
          serious bending) - I think this could be a restriction on the ubiquity of
          OPML that Dave Winer and others appear to be anticipating.

          Cheers,
          Danny.

          ---
          Danny Ayers
          <stuff> http://www.isacat.net </stuff>


          >-----Original Message-----
          >From: christopher_ogden [mailto:christopher_ogden@...]
          >Sent: 05 April 2002 22:44
          >To: opml-dev@yahoogroups.com
          >Subject: [opml-dev] Re: OPML+RDF/XTM?
          >
          >
          >I've thought about combining OPML with RDF and XTM, because RDF and
          >XTM are not well suited for hierarchical content, like OPML is. But
          >it doesn't seem very feasible to connect OPML with RDF and XTM until
          >OPML (or its de facto successors) puts content into an element,
          >rather than into an attribute, like the rest of the XML world.
          >
          >If OPML were more orthodox, you could have RDF, XTM, and even SVG
          >graphics as a node element of an "OPML 2.0" outline. And I don't
          >think any RDF, XTM, or other XML tools, including browsers, would be
          >willing to implement an OPML outline as an element, or xlink to an
          >OPML node, until OPML comes within the XML fold.
          >
          >
          >
          >--- In opml-dev@y..., "Danny Ayers" <danny666@v...> wrote:
          >> Has anyone played with Outline Processor Markup Language (OPML) [1]
          >> alongside RDF or Topic Maps? Not thought this through much but I
          >would
          >> imagine there could be a lot of potential, not least for an RDF or
          >XTM
          >> editor, where you might have an outline view (backed by OPML) with
          >pluggable
          >> semantics (from XTM or RDFS).
          >>
          >> Cheers,
          >> Danny.
          >>
          >> [1] http://www.opml.org
          >>
          >> ---
          >> Danny Ayers
          >> <stuff> http://www.isacat.net </stuff>
          >
          >
          >
          >To unsubscribe from this group, send an email to:
          >opml-dev-unsubscribe@egroups.com
          >
          >
          >
          >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
          >
          >
        • Logan, Patrick D
          ... XTM are not well suited for hierarchical content, like OPML is.
          Message 4 of 9 , Apr 5, 2002
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            >> I've thought about combining OPML with RDF and XTM, because RDF and
            XTM are not well suited for hierarchical content, like OPML is. <<

            Here's an opinion of someone who's done a fair bit of application-specific
            graphical editor and other "information presentation" development, including
            "semantic net" tools for several frame-based reasoning systems. But precious
            little OPML work. (i.e. I wrote tree display for OPML once).

            Any arbitrary graph can be displayed as an outline by selecting the paths to
            be outlined. The outline is one of many possible views of the graph.

            graph ======= Translator to HTML ==> HTML
            + preferences


            graph ======= Translator to OPML ==> OPML
            + preferences

            graph ======= Translator to XTM ==> topic map
            + preferences

            graph N ======= Translator to graph ==> graph N+1
            + preferences

            I think OPML should be seen as a format some devices can display, rather
            than as a general purpose notation.
          • Danny Ayers
            Hi Patrick, ... Is any of this work available online? I ve been working (on and off) on related stuff myself (http://www.isacat.net/2002/svolgo/index.htm), and
            Message 5 of 9 , Apr 6, 2002
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              Hi Patrick,

              >Here's an opinion of someone who's done a fair bit of application-specific
              >graphical editor and other "information presentation" development,
              >including
              >"semantic net" tools for several frame-based reasoning systems.
              >But precious
              >little OPML work. (i.e. I wrote tree display for OPML once).

              Is any of this work available online? I've been working (on and off) on
              related stuff myself (http://www.isacat.net/2002/svolgo/index.htm), and this
              is one field at least where seeing other people's approaches can save vast
              amounts of wasted effort.

              >Any arbitrary graph can be displayed as an outline by selecting
              >the paths to
              >be outlined. The outline is one of many possible views of the graph.
              >
              >graph ======= Translator to HTML ==> HTML
              >+ preferences
              >
              >
              >graph ======= Translator to OPML ==> OPML
              >+ preferences
              >
              >graph ======= Translator to XTM ==> topic map
              >+ preferences
              >
              >graph N ======= Translator to graph ==> graph N+1
              >+ preferences

              Nice way of putting it.

              >I think OPML should be seen as a format some devices can display, rather
              >than as a general purpose notation.

              That makes sense, but including RDF payload would put OPML on the left-hand
              side of the translations above, in fact the 'translation' stage would be
              redundant for :

              OPML (+graph) => OPML-aware app
              OPML (+graph) => RDF-aware app

              Cheers,
              Danny.
            • patrickdlogan
              ... No. I did all this 15 years ago on Lisp machines and I never owned the work myself. I ve been reviving some related ideas, though, in JScheme. This is
              Message 6 of 9 , Apr 6, 2002
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                >> "semantic net" tools for several frame-based reasoning systems <<

                > Is any of this work available online? <

                No. I did all this 15 years ago on Lisp machines and I never owned
                the work myself.

                I've been reviving some related ideas, though, in JScheme. This is
                getting off topic, though, so ob-OPML...

                > ...would put OPML on the left-hand side of the translations... <

                Sure. For my own interests I would draw it like...

                <format-x> => <intermediate-format> => <format-y>

                OPML can be on the left and right, but it's not my choice for the
                middle.
              • Danny Ayers
                ... JScheme? Not seen that yet - I played around with a bit of Scheme (Dr. Scheme) a while ago (trying to think declaratively) I normally work in Java so
                Message 7 of 9 , Apr 7, 2002
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                  >> Is any of this work available online? <
                  >
                  >No. I did all this 15 years ago on Lisp machines and I never owned
                  >the work myself.
                  >
                  >I've been reviving some related ideas, though, in JScheme. This is
                  >getting off topic, though, so ob-OPML...

                  JScheme? Not seen that yet - I played around with a bit of Scheme (Dr.
                  Scheme) a while ago (trying to think declaratively) I normally work in Java
                  so JScheme sounds great.

                  >> ...would put OPML on the left-hand side of the translations... <
                  >
                  >Sure. For my own interests I would draw it like...
                  >
                  ><format-x> => <intermediate-format> => <format-y>
                  >
                  >OPML can be on the left and right, but it's not my choice for the
                  >middle.

                  That much I certainly agree on, though with the kind of architecture I've
                  been playing with, instead of an intermediate format as such you'd have an
                  intermediate representation, within a model in an app.

                  Any further thoughts in this arena would be welcome ;-)

                  Cheers,
                  Danny.
                • christopher_ogden
                  ... individual ... That s great if your goal is merely to annotate an outline. But in OPML you can t readily create an outline of XTM topics or RDF
                  Message 8 of 9 , Apr 9, 2002
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                    --- In opml-dev@y..., "Danny Ayers" <danny666@v...> wrote:
                    > ... The <head> element could contain
                    > document-wide metadata in exactly the same fashion as HTML, and
                    individual
                    > items could also be described like :
                    > <outline text="Heart of Glass.mp3" type="song" f="Blondie - Heart of
                    > Glass.mp3">
                    > <metadata>
                    > ... dc:creator="Debbie Harry" ...
                    > </metadata>
                    > </outline>
                    >
                    > or whatever. Minor changes to the DTD.

                    That's great if your goal is merely to annotate an outline. But in
                    OPML you can't readily create an outline of XTM topics or RDF
                    statements. In other words, though you can annotate an outline, you
                    can't make an outline of annotations and topics.
                  • Danny Ayers
                    ... I ve not spent enough time with TMs to know there, but you certainly can t go from arbitrary RDF - outline directly because of the graph - tree issue. I
                    Message 9 of 9 , Apr 9, 2002
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                      >That's great if your goal is merely to annotate an outline. But in
                      >OPML you can't readily create an outline of XTM topics or RDF
                      >statements. In other words, though you can annotate an outline, you
                      >can't make an outline of annotations and topics.

                      I've not spent enough time with TMs to know there, but you certainly can't
                      go from arbitrary RDF -> outline directly because of the graph -> tree
                      issue.

                      I think perhaps talking in terms of annotations may be misleading in this
                      context, annotations are usually intended to be human-readable and have
                      usually just a single purpose, but RDF is definitely intended for machine
                      consumption and usually XTM is too, and both have a vast number of potential
                      uses.

                      BTW, does an outline really have to be a tree anyway? Wouldn't an outliner
                      that supported graphs be a lot more versatile (a la MindMaps). You could
                      always use it for OPML-style outlines (as a special case, a flag maybe). But
                      would it still be called an outline, or a mindmap ;-)

                      Cheers,
                      Danny.
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