Library infrastructure

Before we go deeper into specific instruments and how to price them, we need to lay some more necessary groundwork.

There are some classes and patterns in QuantLib that define its basic infrastructure—its architecture, if you will—and need to be known so that you can use the library in an idiomatic way, making it work with you and not against you.

These facilities include handles, the base Instrument and PricingEngine class with their interplay, the base behavior of the TermStructure class, quotes, and the Observable pattern embedded in most of the library classes. They are the topic of the next few chapters.