Hi Vojtech, Although an XML document may only have a single document (root) element, an external entity does not have this restriction.
Take for example two documents, foo.xml and bar.xml: foo.xml contains: <!DOCTYPE foo [ <!ENTITY bar SYSTEM "bar.xml"> ]> <foo> &bar; </foo> and bar.xml contains: <bar>one</bar> <bar>two</bar> <bar>three</bar> then foo.xml is well-formed. bar.xml, if used as a standalone document, is not well-formed. I sometimes use this trick for log files. The application writes log entries to the equivalent of bar.xml, one (parent) element per line. When I want to process the log file I use the equivalent of foo.xml. HTHs, Steve Ball On 02/10/2013, at 6:13 PM, Vojtech Fried <vfr...@opentext.com> wrote: > Hi, > > I have a slightly philosophical question. XML specs says that there can be > only one root element in a XML document. However, libxml allows you to have > any number of element children in a document node. Starting from a valid > document, you can add or remove child elements of the document node freely. > You get an error when you try to e.g. save such a document. > > My view is that it is a “loophole”. Single root element is not enforced, > because you could need in some situations to temporarily have an empty > document or a document with multiple root elements. But you should not rely > on it and try to have a single root element most of the time. > > My coworker views it as a “feature” that allows you to e.g. easily merge two > documents into one (they can have different root elements names). And then > use XPaths on this merged document in (almost) the same way as you would with > the two original documents. > > What would you say? Why is there this single root element rule anyway? > > The reason I am asking is that our software was written in a way that > exploits this “loophole” (uses this “feature”), but now when extending some > functionality I get those XML errors. But it is also hard to fix without > breaking backward compatibility… > > Thanks. > > Vojtech > _______________________________________________ > xml mailing list, project page http://xmlsoft.org/ > xml@gnome.org > https://mail.gnome.org/mailman/listinfo/xml
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