Abstractor

An abstractor maintains the mapping between classes of objects and single higher-level objects.

Implementations:

• Abstractor_Disaggregate
  Builds map top-down, splitting each high-level object into an equivalence class.
• Abstractor_Explicit
  User builds map explicitly by specifying links between classes and objects.
• Abstractor_Redescribe
  Builds map bottom-up, abstracting each low-level equivalence class as a single higher-level object according to a Redescribe_Op.

Member functions:

• disaggregate: Abstractor_Disaggregate . Space -> void
  Builds the map for the high-level objects.
• down: Abstractor . SObject -> Space
  Returns the equivalence class abstracted by the high-level object.
• high_level_objects: Abstractor -> Space
  Returns the high-level objects abstracted by the abstractor.
• link: Abstractor_Explicit . Space . SObject -> void
  Builds the map for the low-level equivalence class to/from the high-level object.
• localize: Abstractor_Redescribe . SObject -> Space
  Same as "down."
• low_level_classes: Abstractor -> Classes
  Returns the low-level equivalence classes abstracted by the abstractor.
• redescribe: Abstractor_Redescribe . Classes -> void
  Builds the map for the low-level equivalence classes.
• up: Abstractor . Space -> SObject
  Returns the high-level object abstracting the class.