FUNCTION acyclic_location_relationship
(relation : location_relationship, relatives : SET [0:?] OF location, specific_relation : STRING) : BOOLEAN;
LOCAL
x : SET OF location_relationship;
END_LOCAL;
IF relation.relating_location IN relatives THEN
RETURN (FALSE);
END_IF;
x := QUERY(lctn <* bag_to_set(USEDIN(relation.relating_location, 'LOCATION_SCHEMA.' + 'LOCATION_RELATIONSHIP.' + 'RELATED_LOCATION')) | specific_relation IN TYPEOF(lctn));
REPEAT i := 1 TO HIINDEX(x);
IF NOT acyclic_location_relationship(x[i], relatives + relation.relating_location, specific_relation) THEN
RETURN (FALSE);
END_IF;
END_REPEAT;
RETURN (TRUE); END_FUNCTION; -- acyclic_location_relationship
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