Intensional HTML
Date
1997
Authors
Yildirim, Taner
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Abstract
Intensional HTML (IHTML) is a high-level authoring language for the World Wide Web that makes it practical to specify pages and sites that exist in many different versions or variants using standard client and server software.
Each IHTML page defines an intension - an indexed family of actual (extensional) HTML pages which varies over a multi-dimensional author-specified version space. The version space is partially ordered by a refinement/specialization ordering. For example, platform:macintosh can be refined to platform:macintosh+language:french or to platform:macintosh%68k and the latter two both refine to platform:macintosh%68k + language.french.
Authors can create multiple labeled versions of the IHTML source for a given page. Requests from clients specify both a page and a version, and the server-side software selects the appropriate source page and uses it to generate the requested actual HTML page. The clients request versions of pages simply by clicking on intensional/transversion links, which look like standard hypertext links, provided by IHTML authors. From the client point of view, a multi-versioned site is nothing but a huge site with static clones created for each existing version of all pages.
Authors do not, however, have to provide separate sources for each version. If the server-side software can not find a source page with the exact version requested, it uses the page whose label most closely approximates the requested version. In other words, it treats the refinement ordering as an (reverse) inheritance ordering. Thus different versions can share source, and authors can write generic, multi-version code.