Tompa: Experiences with the OED

Tompa, "Experiences with the OED"

3. Support for elastic typography

One major advantage gained by adopting descriptive markup is the flexibility to format a text to suit various media and uses (Fawcett, 1989). In particular, the tagging used in the OED does not bind a display engine to produce a particular form. In fact, it is left completely to the users' discretion to design text formats that will display extractions from the OED to best advantage. To this end, a user must create a specification file, or style sheet, that correlates tags in the text with presentational features -- more typically a user requests that some pre-defined specification file is to be applied. This style sheet is then interpreted by the Lector text display system (Raymond, 1990), to produce a presentation form on a screen (through the X Windows System).

For the OED, we have created a file that includes style sheets for standard display (mimicking the printed style of the OED) (Figure 4); standard display but with quotations suppressed; one-per-line display of quotations only; standard display of definitions only or of etymologies and dates only; outline displays of the sense structure showing the upper skeleton only, the complete sense skeleton (Figure 5), or the skeleton with all lemmas shown as well; and a standard display augmented by display of all tags (Figure 6), as well as a completely uninterpreted dump of the characters (including tags) as they are stored.

A display specification for Lector is itself represented as a tagged text (Lector, 1990). After declaring the fonts that are to be made available to the display device, the file includes a series of style sheet declarations (indicated by <Spec>...</Spec>). Each style sheet is assigned a name and its default display mode.

   <Spec>
      <Name>Standard</Name>
      <Family>Times</Family>
      <Type>Roman</Type>
      <Size>14</Size>
      <PrText>on</PrText>
      <PrTag>off</PrTag>
      ...
   </Spec>
   <Spec>
      <Name>Quotes Only</Name>
      <Family>Times</Family>
      <Type>Bold</Type>
      <Size>12</Size>
      <PrText>off</PrText>
      <PrTag>off</PrTag>
      ...
   </Spec>

Following that, for each tag that can appear in the text, the style sheet indicates what typesetting is to be done: change in font or style, line break, indentation, insertion of a character string, suppression of text from the file, and so forth. For example, the "Quotes Only" style sheet includes the following directives:

<Tag> <Name>Q</Name> <PrText>on</PrText> </Tag> <Tag> <Name>/Q</Name> <PrText>off</PrText> <LineBreak>on</LineBreak> </Tag> <Tag> <Name>D</Name> <Type>Bold</Type> </Tag> <Tag> <Name>/D</Name> <Type>Roman</Type> </Tag> <Tag> <Name>A</Name> <Type>Small Caps</Type> </Tag> <Tag> <Name>/A</Name> <Type>Roman</Type> </Tag> <Tag> <Name>W</Name> <Type>Italic</Type> </Tag> <Tag> <Name>/W</Name> <Type>Roman</Type> </Tag> <Tag> <Name>T</Name> <Type>Roman</Type> </Tag> <Tag> <Name>SQ</Name> <String>[</String> </Tag> <Tag> <Name>/SQ</Name> <String>]</String> </Tag>

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