Attributes

Components can have attributes associated with them. Attributes are additional items of information describing some aspect of the component. For example, the dependency attribute, `dep', identifies another component on which the component depends; the `data' component may depend on either the positions or the connections component, depending on circumstances. Alternatively the component `ref' indicates that a component refers to another component. Typically the connections component will have a `ref' of `positions', indicating that the connections refer to the positions.