Good programmers write good code. Great programmers write programs to generate it.
Automation is the holy grail of software development. In fact, much of the progress in software development is driven by the notion of code generation from some higher-level specification. After all, isn't that what assemblers and compilers do? However, in another form of code generation, the target language is not executable machine code, but a high-level language such as Java or C++. Why would you want to generate code in this way, and what does XML have to do with it?
When you write programs, you essentially encode many kinds of knowledge into a very specific syntax that is optimized for one particular development life-cycle phase. It is difficult to leverage the work done in coding to other important development tasks because programming languages are difficult to parse and much of the interesting information is encoded in ad-hoc comments. Representing application knowledge in XML provides the opportunity for much greater leverage. From XML specifications, you can generate application code, test programs, documentation, and possibly even test data. This is not to say that XML gives you this for free. As with all software-development tasks, a great deal of planning and infrastructure building is required to reap the benefits.
This chapter is different from most other chapters in this book because most examples are components of a solution within the ...