package org.archstudio.prolog.op.iso;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.archstudio.prolog.engine.PrologUtils;
import org.archstudio.prolog.engine.ProofContext;
import org.archstudio.prolog.engine.UnificationEngine;
import org.archstudio.prolog.op.Executable;
import org.archstudio.prolog.term.ComplexTerm;
import org.archstudio.prolog.term.Term;
import org.archstudio.prolog.term.VariableTerm;
public class AlphaLessThan extends ComplexTerm implements Executable {
public AlphaLessThan(String name, List<? extends Term> terms) {
super(name, 2, terms);
}
@Override
public Iterable<Map<VariableTerm, Term>> execute(ProofContext proofContext, UnificationEngine unificationEngine,
Term source, Map<VariableTerm, Term> variables) {
String n1 = PrologUtils.resolveString(proofContext, getTerm(0), variables);
String n2 = PrologUtils.resolveString(proofContext, getTerm(1), variables);
return n1.compareTo(n2) < 0 ? Collections.singleton(variables) : PrologUtils.emptyVariablesList();
}
}