src/builtin/PRED_$get_level_1.java

package com.googlecode.prolog_cafe.builtin;
import com.googlecode.prolog_cafe.lang.IntegerTerm;
import com.googlecode.prolog_cafe.lang.Operation;
import com.googlecode.prolog_cafe.lang.Predicate;
import com.googlecode.prolog_cafe.lang.Prolog;
import com.googlecode.prolog_cafe.lang.Term;
/**
 <code>'$get_level'/1</code><br>
 @author Mutsunori Banbara (banbara@kobe-u.ac.jp)
 @author Naoyuki Tamura (tamura@kobe-u.ac.jp)
 @version 1.0
*/
public class PRED_$get_level_1 extends Predicate.P1 {
    public PRED_$get_level_1(Term a1, Operation cont) {
        arg1 = a1;
        this.cont = cont;
    }

    @Override
    public Operation exec(Prolog engine) {
	//        engine.setB0(); 
	Term a1;
        a1 = arg1;
        if (! a1.unify(new IntegerTerm(engine.B0), engine.trail)) {
            return engine.fail();
        }
        return cont;
    }
}