Funcons-beta : Objects.cbs | PRETTY | PDF

Objects

[
  Datatype objects
  Funcon   object
  Funcon   object-identity
  Funcon   object-class-name
  Funcon   object-feature-map
  Funcon   object-subobject-sequence
  Funcon   object-tree
  Funcon   object-single-inheritance-feature-map
]

Datatype
  objects ::= object(_:atoms, _:identifiers, _:environments, _:objects*)

object( A, C, Env, O*) is an object:

• distinguished by an atom A,
• of a class named C,
• with an environment Env with the features of the object, and
• a sequence O* of subobjects of the direct superclasses of C. object( A, C, Env) is an object of a base class. object( A, C, Env, O′) is an object of a class with a single superclass. With multiple inheritance, subobjects due to repeated inheritance of the same class may be shared.

Implementations of objects generally represent an object as a vector of fields, and use pointers and offsets for efficient access to individual fields. The representation of objects used in this specification is independent of such implementation concerns.

Funcon
  object-identity(_:objects) : =>atoms
Rule
  object-identity
    object(A:atoms, _:identifiers, _:environments, _*:objects*) ~> A

Funcon
  object-class-name(_:objects) : =>identifiers
Rule
  object-class-name
    object(_:atoms, C:identifiers, _:environments, _*:objects*) ~> C

Funcon
  object-feature-map(_:objects) : =>environments
Rule
  object-feature-map
    object(_:atoms, _:identifiers, Env:environments, _*:objects*) ~> Env

Funcon
  object-subobject-sequence(_:objects) : =>objects*
Rule
  object-subobject-sequence
    object(_:atoms, _:identifiers, _:environments, O*:objects*) ~> O*

Funcon
  object-tree(_:objects) : =>trees(objects)

object-tree O forms a tree where the branches are the object trees for the direct subobjects of O.

Rule
  object-tree(O:objects)
   ~> tree(O,
        interleave-map (
          object-tree given,
          object-subobject-sequence O))

Funcon
  object-single-inheritance-feature-map(O:objects) : =>environments
   ~> map-override left-to-right-map(
        object-feature-map given,
        single-branching-sequence object-tree O)

For multiple inheritance, different resolution orders can be specified by using difference linearisations of the object tree.

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