7.2  Term unification

• (=)/2 - Prolog unification
• unify_with_occurs_check/2
• (\=)/2 - not Prolog unifiable

7.2.1  (=)/2 - Prolog unification

Templates

=(?term, ?term)

Description

Term1 = Term2 unifies Term1 and Term2. No occurs check is done, i.e. this predicate does not check if a variable is unified with a compound term containing this variable (this can lead to an infinite loop).

= is a predefined infix operator (section 7.14.10).

Errors

None.

Portability

ISO predicate.

7.2.2  unify_with_occurs_check/2

Templates

unify_with_occurs_check(?term, ?term)

Description

unify_with_occurs_check(Term1, Term2) unifies Term1 and Term2. The occurs check test is done (i.e. the unification fails if a variable is unified with a compound term containing this variable).

Errors

None.

Portability

ISO predicate.

7.2.3  (\=)/2 - not Prolog unifiable

Templates

\=(?term, ?term)

Description

Term1 \= Term2 succeeds if Term1 and Term2 are not unifiable (no occurs check is done).

\= is a predefined infix operator (section 7.14.10).

Errors

None.

Portability

ISO predicate.