Where Are We?

XML layers type and structure over information. An XML document combines one or more serialized entities to form a single data object that is treated as a whole. The XML document is then decomposed into one or more named elements, each of which consists of an unordered sequence of uniquely named attributes and an ordered sequence of character data, child elements, and processing instructions. The XML Information Set specification puts shape around these abstractions and the XML 1.0 and Namespaces in XML specifications define the concrete transfer syntax. The next chapter will look at how the XML Information Set is exposed to software agents via programmatic interfaces.