Robust intra-document locations

Several types of existing and next-generation hypertext functionality, incl uding external hyperlinks, annotations, and transclusions, rely on referenc es to locations within another resource. If the document domain cannot guar antee referential integrity, but rather is more like the World Wide Web, in which documents change regularly and without notification, potentially inv alidating internal location references, it is crucial to build robustness i nto the intra-document location resolution mechanism, so that locations con tinue to function even as documents change chaotically. This paper aims to begin a process to evolve a standard for (normative) robust location descri ptors and (non-normative) reattachment algorithms. We discuss criteria for evaluating the robustness of an intra-document location mechanism. Then we describe robust locations, an approach we believe meets these criteria. Rob ust locations include a standard minimal location descriptor and a recommen ded reattachment algorithm. We also suggest what can be done when the chang es are so great that location resolution is problematic. Finally, we descri be the implementation of robust locations within the Multivalent Document s ystem. (C) 2000 Published by Elsevier Science B.V. All rights reserved.