A grammar not only provides syntax but semantics of symbols as well. Semantics is the meaning of a symbol in a given context. The resulting syntax is indeed simple and yet powerful enough for our goals. Actors are the atomic building stones of the language. Compound objects - compound objects formalize how objects can be grouped together to create new meanings, or derive concepts from known actors.
Compound objects allow condensing and expanding and are used for creating an object hierarchy model.
Relations - relation objects create defined relationships among objects. Relations can describe actions, cause-effect relationships, and many more. The exact syntax and its implications will be discussed in Chapter 4 .