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Bottom-up Sections

From: Stefan Ram <ram@ZEDAT.FU-Berlin.DE>
Date: Fri, 8 Aug 2003 04:26:56 +0200
To: www-html@w3.org
Message-ID: <20030808022656.GA11052569@CIS.FU-Berlin.DE>

  Bottom-up Sections

    Abstract: The definition elements dt and dd should be replaced
    by a more general "bottom-up section" element with a "title" and
    a "contents".

  In several types of texts certain "small sections" appear, which
  do not fit into the XHTML 2 section scheme. For example, in articles,
  sometimes there are "boxes" treating certain topics or, in mathematics
  texts, there are labeled theorems or proofs.

  Such a proof can not be easily implemented using the XHTML 2 section
  element, because its "level" then would depend on the level of the
  containing section, while it should always be the same "low" level -
  independent of whether it is part of a section or a chapter.

  The best approximation might be to use a definition list for it,
  where a name like "proof 2.14" is the definition term and the
  text is the definition description. But using a definition list 
  for this case seems somewhat abusive because a proof is not a 
  definition and a proof is not a list.

  A pair of dt and dl elements can be regarded as a definition, but
  this definition pair lacks orthogonality: Why must it always be
  part of a list? Why do we have such a pair for a definition but
  not for a resource description or a picture caption?

  So one might consider to replace the dt-dl-pair by a more
  general element: The "bottom-up section" ("bos"). Its "level" 
  does not derive from the level of the containing section but  
  from the level of the contained sections, therefore the name 

  It consists of 

    * a title (like the definition term)
    * a contents (like the definition description)
    * an optional role-attribute for the title
      (like, e.g., "dt")
    * an optional role-attribute for the contents
      (like, e.g., "dd")

  It may also appear where a list item may appear in an ordered 
  or unordered list, therefore a definition list can now be built
  using the bottom-up section element and one of the list
  elements, like the following unordered list of definitions.
  (A list containing only a certain type of elements can
  be marked as such using the containsonly-attribute.)
    <ul containsonly="definitions">
      <bos isa="definition">
        <title role="dt">Flower</title>
        <contents role="dd">The reproductive part of a plant</contents>

  But such a definition-bos might as well be used outside
  of a list, where ever a paragraph might appear.

  Some values of the attribute "isa" and the attribute "role" 
  should be standardized, like a caption-picture-role, so that
  the element might be used as a picture-caption-pair, as follows

    <bos isa="titled picture">
      <title role="caption">A Flower</title>
      <contents role="picture"><object .../></contents>

  CSS should be extended so as to allow to specify, where the 
  caption appears in relation to the contents (e.g., above or below).

  A proof then might be written as follows.
    <bos isa="proof">
      <contents>(Left as an exercise to the reader.)</contents>

  An FAQ-list as follows.
    <ol containsonly="FAQ-entries">
      <bos isa="FAQ-entry">
        <title role="question">What is a Flower?</title>
        <contents role="answer">The reproductive part of a plant</contents>

  The possible values for the attributes "containsonly", "isa" and 
  "role" should be standardized, a generic use is possible for cases 
  not part of the standard by using the class-attribute as in

      <bos class="exercise-question">
        <contents>What is a flower?</contents>

  Some types of sections might have multiple possible contents-roles:
      <bos class="book description">
        <title role="book title">Flowers</title>
        <contents role="book ISBN">0-937383-18-X</contents>
        <contents role="book description">It is about flowers.</contents>

  Some examples of applications include

    * A definition with a term and a description
    * A titled picture with a caption and a picture
    * A description of a book or other resource
    * A text type (isa) such as
      - a proof
      - a theorem
      - an example
      - a warning/caveat
      - an abstract, a conclusion
      - a comment
      - a listing
      - a BNF production
      - a background information
      - an exercise

Received on Thursday, 7 August 2003 22:33:22 UTC

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