Examples with IntervalAtom at.ac.tuwien.kr.alpha.core.atoms.IntervalAtom used on opensource projects

Example 1 with IntervalAtom

use of at.ac.tuwien.kr.alpha.core.atoms.IntervalAtom in project Alpha by alpha-asp.

the class IntervalTermToIntervalAtom method rewriteIntervalSpecifications.

/**
 * Rewrites intervals into a new variable and special IntervalAtom.
 *
 * @return true if some interval occurs in the rule.
 */
private static NormalRule rewriteIntervalSpecifications(NormalRule rule) {
    // Collect all intervals and replace them with variables.
    Map<VariableTerm, IntervalTerm> intervalReplacements = new LinkedHashMap<>();
    List<Literal> rewrittenBody = new ArrayList<>();
    for (Literal literal : rule.getBody()) {
        Literal rewrittenLiteral = rewriteLiteral(literal, intervalReplacements);
        if (rewrittenLiteral != null) {
            rewrittenBody.add(rewrittenLiteral);
        }
    }
    // Note that this cast is safe: NormalHead can only have a BasicAtom, so literalizing and getting back the Atom destroys type information,
    // but should never yield anything other than a BasicAtom
    NormalHead rewrittenHead = rule.isConstraint() ? null : Heads.newNormalHead((BasicAtom) rewriteLiteral(rule.getHead().getAtom().toLiteral(), intervalReplacements).getAtom());
    // If intervalReplacements is empty, no IntervalTerms have been found, keep rule as is.
    if (intervalReplacements.isEmpty()) {
        return rule;
    }
    // Add new IntervalAtoms representing the interval specifications.
    for (Map.Entry<VariableTerm, IntervalTerm> interval : intervalReplacements.entrySet()) {
        rewrittenBody.add(new IntervalAtom(interval.getValue(), interval.getKey()).toLiteral());
    }
    return new NormalRuleImpl(rewrittenHead, rewrittenBody);
}