DISCUSSION

  This section discusses some important implementation issues. We first briefly present a well-accepted algorithm in subsection 6.1 for maintaining temporal relationships between messages. The support of transaction is discussed in subsection 6.2. Subsection 6.3 discusses the semantics of the event constructs introduced in section 4. In subsection 6.4 we show how to specify messaging policies for more flexibility. Subsection 6.5 illustrates how to specify some predicates which were introduced as built-in predicates in section 4 using the language itself. Backtracking is discussed in subsections 6.6.