Chapter 1. XML and the Web
And what if all of animated nature
Be but organic Harps diversely fram'd,
That tremble into thought, as o'er them sweeps
Plastic and vast, one intellectual breeze ,
At once the Soul of each, and God of all?
SAMUEL TAYLOR COLERIDGE, The olian Harp
XML itself, once you get used to its syntax and terminology, is surprisingly simple. It sounds suspiciously like common sense: When you see something you can name , do it . The basic rules for writing these names can be taught to a six year old. How can such a simple thing precipitate such a powerful revolution?
Yet the revolution is raging, fueled in part by XML's simplicity and accessibility. Decades-old speculations about "programming languages of the future" totally missed the point: The modern computing landscape is shaped not by some radically new programming language but by a simple and flexible common data format, XML. Indeed, XML is revolutionarynot in what it offers but in what it lets you do without.
The simpler a thing is, the more dependent it is on interpretation. And interpretations are plenty. The simple XML root underlies an already huge and explosively growing tree of standards, technologies, tools, and lore. Each XML book must begin by charting its own course in this brave new world.
In this chapter, we touch on a wide range of subjects, all of which are important for understanding the techniques described in the rest of the book. It's not your typical XML intro; I cover only those concepts that bubble up every day in practical XML work, and therefore those I can say something useful (and, hopefully, nontrivial) about. Actually, this chapter was the last to be written, but it does make sense to read it first.