Why use an empty element in XML?

Question

Rank amateur here. I get the instructions on HOW to use an empty element in XML. But why would you? What would it be used for, other than (I guess) to add a blank record when th

Answer 1

I think you are using "empty" elements to mean "elements with no children of any kind." Self-closing elements -- ones which don't have a separate closing tag -- may still have attributes and aren't empty in that sense.

(X)HTML itself defines "empty" elements, such as
. Again, even
may have class and other attributes.

To the question of how they might be used in your own schemas, you can use empty XML elements as "markers" (borrowing from the way that .NET uses the term "marker interface" for an interface with no members). This is useful when you want to add a "boolean" attribute to an element (like HTML allows valueless attributes such as checked). In such cases, using an attribute would force you to add noise of some kind (in the form of a meaningless or empty value).

I use it this way, for example, to mark speeches as prose in Shakespeare plays:

    Archidamus
    
    If you shall chance, Camillo, to visit Bohemia, on
    the like occasion whereon my services are now on
    foot, you shall see, as I have said, great
    difference betwixt our Bohemia and your Sicilia.

That said, it is kind of a kludge to work around what can be seen as a defect of XML, viz, the inability to represent non-text primitives.