Prolog Language Logical Purity Unification
Example
Unification is a pure relation. It does not produce side effects and can be used in all directions, with either or both arguments fully or only partially instantiated.
In Prolog, unification can happen
- explicitly, using built-in predicates like
(=)/2orunify_with_occurs_check/2 - implicitly, when unification is used for selecting a suitable clause.
