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.. rst-class:: align-right

built-in predicate

.. index:: pair: instantiates_class/2-3; Built-in predicate .. _predicates_instantiates_class_2_3:

instantiates_class/2-3

Description

::

instantiates_class(Instance, Class) instantiates_class(Instance, Class, Scope)

Enumerates, by backtracking, all pairs of objects such that the first one instantiates the second. The relation scope is represented by the atoms public, protected, and private.

Modes and number of proofs

::

instantiates_class(?object_identifier, ?object_identifier) - zero_or_more instantiates_class(?object_identifier, ?object_identifier, ?scope) - zero_or_more

Errors

| Instance is neither a variable nor a valid object identifier: | type_error(object_identifier, Instance) | Class is neither a variable nor a valid object identifier: | type_error(object_identifier, Class) | Scope is neither a variable nor an atom: | type_error(atom, Scope) | Scope is an atom but an invalid entity scope: | domain_error(scope, Scope)

Examples

::

% check that the water_jug is an instante of state_space: | ?- instantiates_class(water_jug, state_space).

% enumerate the state_space instances where the % instantiation relation is public: | ?- instantiates_class(Space, state_space, public).

.. seealso::

:ref:predicates_current_object_1, :ref:predicates_extends_object_2_3, :ref:predicates_specializes_class_2_3