extends_category/2-3

Description

extends_category(Category, ParentCategory)
extends_category(Category, ParentCategory, Scope)

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

Modes and number of proofs

extends_category(?category_identifier, ?category_identifier) - zero_or_more
extends_category(?category_identifier, ?category_identifier, ?scope) - zero_or_more

Errors

Category is neither a variable nor a valid protocol identifier:
type_error(category_identifier, Category)
ParentCategory is neither a variable nor a valid protocol identifier:
type_error(category_identifier, ParentCategory)
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

% enumerate the categories extended by the derailleur category:
| ?- extends_category(derailleur, Category).

% enumerate categories that privately extend the basics category:
| ?- extends_category(Category, basics, private).