Bowerbird wrote:
jeroen said:
Some have argued (with valid reasons) that the entire idea of TEI markup is broken, and have proposed systems in which the mark-up is separated from the text (stream of characters), in such a way that multiple, parallel systems of mark-up can exist. Think of a separate (part of a) file, saying characters 21 to 34 are italics, and so on. This may sound odd, but it is the way the old Macintosh wordprocessor MacWrite worked.
actually, that's the way the underlying _editfield_ of the (classic) mac operating system is structured.
I was told by someone (who I think is in the know) that the idea of separating markup from content (by having layers) was first proposed years ago by Ted Nelson of "Project Xanadu" fame. I recall asking Dr. Stephen DeRose at Brown University (one of the world's leading electronic document experts) about Ted Nelson's proposal and how it compares with SGML/XML markup. Dr. DeRose's reply was essentially that layering has some obvious advantages (i.e., easier to represent non-hierarchical structures), but that there were a lot of real world disadvantages as well. In the early days, before SGML, the researchers were exploring all kinds of avenues, and nearly all of them moved in the direction of direct markup rather than Ted Nelson's layering. Of course, one wonders if the dynamics have changed enough that revisiting the issue would yield a different result. Can't answer that, but other than being able to non-hierarchically "markup" documents with layering, I do not see any compelling advantages -- there'd have to be some whole new killer application which requires such layering to work properly, and I've not seen such an application arise the last few years.. (It is possible in XML to do some non-hierarchical markup using empty "milemarkers" with ID/IDREF pairs. But one would have to build a special application to read such documents -- that's no different than building an application to process the "layer" approach. An example of non-hierarchical documents is the modern Bible, where verses can cross sentence and even paragraph boundaries. So one has the choice in SGML/XML of marking it up by chapter/paragraphs, and put in verse "milemarkers", or the opposite. Most would agree that one applies hierarchical markup to document structure (paragraphs), and then add milemarkers to locate the start of a new verse.) Jon