[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] My 5 paragraphs
I decided that it wasn't very helpful to punt on my own suggestion. A few <P>'s on whitespace follow. Adapt/preserve/wrap-fish-in them as you like. Whitespace in XML is always signficant wherever data may appear. This means that XML truly treats each character that is not inside a tag or a comment as a potentially meaningful piece of information. As comments are generally not significant to most applications (but must be preserved by editors and other transduction processes), whitespace in a few contexts is generally best not made the crux of a critical distinction: For instance, in an element whose sole allowed content according to the DTD is other elements (SGML term: element content) it is probably a bad idea to base processing semantics on the presence or absence of whitespace. However, since linking depends critically on where any characters not in tags occur, even such space should not be casually deleted, as it may cause hyperlinks in other documents to break. This happens because hyperlinks have to be able to count sub-parts of an element's content, and the whitespace between two elements is such a sub-part. XML provides some hints as to the treatment of whitespace in the SPACE attribute. For most applications like browsing or typesetting or importing into a databse, normalizing such whitespace should be harmless to the semantic content. You might break links in these cases as well, but any change can break a link. If you are creating and editing or transduction application, you should _not_ change any whitespace without explicit authorization from the author -- auch changes may damage links and file offsets that the user wants to preserve. This is the same kind of restriction as you must observe when editing an XML file with comments or PIs in it. Even if you don't use or understand these, they must be preserved in the general case. In sum, there are 2 kinds of applications that can use XML: Those, like editors, that should preserve all information, they can (including all whitespace, comments, PIs, etc), unless instructed otherwise. We might call these transduction applications, because they produce a representation of the document they read as their output. The other sort of application -- call them processing applications -- is responsible for processing the results of an XML parser, and may ignore comments and PIs, normalize whitespace (as warranted by knowledge of the DTD, tags, or XML-SPACE hints), and so forth. Such applications are generally creating a specific view or result from the data in an XML document, and may do that in any way that produces the desired result. -- David _________________________________________ David Durand dgd@c... \ david@d... Boston University Computer Science \ Sr. Analyst http://www.cs.bu.edu/students/grads/dgd/ \ Dynamic Diagrams --------------------------------------------\ http://dynamicDiagrams.com/ MAPA: mapping for the WWW \__________________________ xml-dev: A list for W3C XML Developers Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ To unsubscribe, send to majordomo@i... the following message; unsubscribe xml-dev List coordinator, Henry Rzepa (rzepa@i...)
|
PURCHASE STYLUS STUDIO ONLINE TODAY!Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced! Download The World's Best XML IDE!Accelerate XML development with our award-winning XML IDE - Download a free trial today! Subscribe in XML format
|