NEL Used as a Line Break

The fourth change XML 1.1 makes is of no use to anyone and should never have been adopted. XML 1.1 allows the Unicode next line character (#x85, NEL) to be used anywhere a carriage return, line feed, or carriage returnline feed pair is used in XML 1.0 documents. Note that a NEL doesn't mean anything different than a carriage return or line feed. It's just one more way of adding extra white space. However, it is incompatible not only with the installed base of XML software but also with all the various text editors on UNIX, Windows, Mac, OS/2, and almost every other non-IBM platform on Earth. For instance, you can't open an XML 1.1 document that uses NELs in emacs, vi, BBEdit, UltraEdit, jEdit, or most other text editors and expect it to put the line breaks in the right places. Figure 3-1 shows what happens when you load a NEL-delimited file into emacs. Most other editors have equal or bigger problems, especially on large documents.

Figure 3-1. Loading a NEL-Delimited File into a Non-IBM Text Editor


If so many people and platforms have such problems with NEL, why has it been added to XML 1.1? The problem is that there's a certain huge monopolist of a computer company that doesn't want to use the same standard everyone else in the industry uses. Andsurprise, surpriseits name isn't Microsoft. No, this time the villain is IBM. Certain IBM mainframe software, particularly console-based text editors like XEdit and OS/390 C compilers, do not use the same two line-ending characters (carriage return and line feed) that everybody else on the planet has been using for at least the last twenty years . Instead those text editors use character #x85, NEL.

If you're one of those few developers writing XML by hand with a plain console editor on an IBM mainframe, you should upgrade your editor to support the line-ending conventions the rest of the world has standardized on. If you're writing C code to generate XML documents on a mainframe, you just need to use \x0A instead of \n to represent the line end. (Java does not have this problem.) If you're reading XML documents, the parser should convert the line endings for you. There's no need to use XML 1.1.

Effective XML. 50 Specific Ways to Improve Your XML
Effective XML: 50 Specific Ways to Improve Your XML
ISBN: 0321150406
EAN: 2147483647
Year: 2002
Pages: 144 © 2008-2017.
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