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## 3 The object model of asdf

asdf is designed in an object-oriented way from the ground up. Both a system's structure and the operations that can be performed on systems follow a protocol. asdf is extensible to new operations and to new component types. This allows the addition of behaviours: for example, a new component could be added for Java JAR archives, and methods specialised on `compile-op` added for it that would accomplish the relevant actions.

This chapter deals with components, the building blocks of a system, and operations, the actions that can be performed on a system.