terms.pl -- SICStus 4-compatible library(terms).

To be done

- This library is incomplete. As of SICStus 4.6.0, the following predicates are missing:

term_variables_set(@Term, -Variables) is det

Same as term_variables_bag/2, but Variables is an ordered set.

subsumeschk(+Generic, @Specific) is semidet

SICStus 4 name of subsumes_chk/2.

deprecated: - Replace by subsumes_term/2.

term_order(@X, @Y, -R) is det

Same as compare/3, except for the order of arguments.

deprecated: - Use the standard compare/3 instead.

Re-exported predicates

The following predicates are exported from this file while their implementation is defined in imported modules or non-module files loaded by this module.

term_variables_bag(+Term, -Variables) is det

Variables is a list of variables that appear in Term. The variables are ordered according to depth-first left-right walking of the term. Variables contains no duplicates. This is the same as SWI-Prolog's term_variables/2.

contains_term(+Sub, +Term) is semidet

Succeeds if Sub is contained in Term (=, deterministically)

contains_var(+Sub, +Term) is semidet

Succeeds if Sub is contained in Term (==, deterministically)

free_of_term(+Sub, +Term) is semidet

Succeeds of Sub does not unify to any subterm of Term

free_of_var(+Sub, +Term) is semidet

Succeeds of Sub is not equal (==) to any subterm of Term

occurrences_of_term(@SubTerm, @Term, ?Count) is det

Count the number of SubTerms in Term that unify with SubTerm. As this predicate is implemented using backtracking, SubTerm and Term are not further instantiated. Possible constraints are enforced. For example, we can count the integers in Term using

?- freeze(S, integer(S)), occurrences_of_term(S, f(1,2,a), C).
C = 2,
freeze(S, integer(S)).

See also: - occurrences_of_var/3 for an equality (==/2) based variant.

occurrences_of_var(@SubTerm, @Term, ?Count) is det

Count the number of SubTerms in Term that are equal to SubTerm. Equality is tested using ==/2. Can be used to count the occurrences of a particular variable in Term.

See also: - occurrences_of_term/3 for a unification (=/2) based variant.

sub_term(-Sub, +Term)

Generates (on backtracking) all subterms of Term.

Undocumented predicates

The following predicates are exported, but not or incorrectly documented.