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Subject: Innheritance and references
Many comments are indicative of an inadequate explanation of references and inheritance. These subjects are introduced in Section 5, which plunges immediately into a discussion of the structure of Gluons. What follows is an early draft of a proposed new beginning of Section 5, from an improved title, to an introduction to inheritance, and to some introduction of terminology. This work is based on some of Bill’s work, as submitted last week. It would be followed by the current 5.1.1.1, introducing the Gluon, which would be renumbered 5.2. Comments welcome. 5.0 Working with sequences: referencing, modifying, and remote access Sequences can define specific progressions of performance or state within a wide range of services and specifications. They become more useful as they can be re-used, or modified. A sequence that is not fully specified can be adapted and re-used without re-statement. An abstract sequence can become a service through iterative referencing. As a sequence is reified through reference, WS-Calendar specifies how additional information is applied or not applied to each interval through a chain of references. We refer to this process as inheritance. Derivative specification can take advantage of inheritance by defining specific rules that conform to the WS-Calendar inheritance pattern. This section describes how to create references to sequences, including remote references, the rules that allow schedule-related information to become more complete through those references, and how to specify conforming rules in derivative specifications. 5.1 References and Inheritance. Sequences are composed of intervals for which a set of temporal relations have been defined. [RFC5545] also defines the “parent”, “child” and “sibling” relationships, in which one component references another by UID. In WS-Calendar, we reference a sequence by creating a relationship with any single interval in the sequence. We refer to the interval within a sequence that has this relationship as the Designated Interval. Wherever there is “missing” information in the Designated Interval, it can be inherited is inherited from the referring component; we use the “parent” relationship to reference the designated interval. These references may be local or remote. Some, but not all, of the information can be inherited by the other intervals in the sequence. Adding additional references can further specify information in the sequence through inheritance; these additional references created by specifying an additional component that has a parent relation to the previous referring component. In this way, we can create a grand-parent and a great grand-parent. Each parent bequeaths information to its child. A child inherits this information in accord with the inheritance rules. If the child is itself a parent, it bequeaths its information, the bound result of its internal information and its inheritance, to its child. Information to complete the specification of a sequence flows in this way from parent to child, from the outer reference to the inner sequence. Inheritance by the designated interval is governed by slightly different inheritance rules than the other intervals in the sequence. In particular, only the designated interval can inherit the start date and time from its parent. The starting date and times if other intervals in a sequence are computed using the temporal relationships within the sequence. Other information can be inherited by all intervals in a sequence. Full inheritance rules are specified at [reference]. The referring components are called Gluons. In physics, gluons are particles that affect the exchanges of force between quarks, but are not themselves quarks. By analogy, WS-Calendar Gluons affect the referencing and binding of intervals in a sequence, but are not themselves intervals or part of sequences. Because intervals can inherit almost any property from a Gluon, Gluons must contain most of the same information elements as Intervals. Because Intervals can contain information payloads for specifications that use WS-Calendar, and these payloads can inherit information from gluons in the same way intervals do, Gluons must be able to contain information payloads from those specifications as well. Gluons are discussed in the next section. “It is difficult to get a man to understand something, when his salary depends upon his not understanding it” -- Upton Sinclair.
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