DeepStackTest.java

package com.igormaznitsa.prol.test;

import com.igormaznitsa.prol.data.Term;
import com.igormaznitsa.prol.data.TermInteger;
import com.igormaznitsa.prol.data.TermList;
import com.igormaznitsa.prol.io.DefaultProlStreamManagerImpl;
import com.igormaznitsa.prol.logic.Goal;
import com.igormaznitsa.prol.logic.ProlContext;
import com.igormaznitsa.prol.parser.ProlConsult;
import com.igormaznitsa.prol.utils.Utils;
import junit.framework.TestCase;
import org.junit.Ignore;
import org.junit.Test;

@Ignore
public class DeepStackTest extends TestCase {

  private TermList makeList(final int depth) throws Exception {
    final ProlContext context = new ProlContext("test", DefaultProlStreamManagerImpl.getInstance());
    final ProlConsult consult = new ProlConsult("depth(0,[]):-!.depth(X,R):-X1 is X-1, depth(X1,R2), R=[X|R2].", context);
    consult.consult();
    final String goalText = "depth(" + depth + ", R).";
    final Goal goal = new Goal(goalText, context);
    final Term resultterm = goal.solve();
    assertNotNull(resultterm);
    final TermList result = (TermList) goal.getVarForName("R").getValue();
    return result;
  }

  private boolean checkList(int depth, TermList list) {
    TermList cList = list;
    while (!cList.isNullList()) {
      final TermInteger intterm = (TermInteger) Utils.getTermFromElement(cList.getHead());
      if (depth != intterm.getValue()) {
        return false;
      }
      depth--;
      cList = (TermList) Utils.getTermFromElement(cList.getTail());
    }
    return true;
  }

  @Test
  public void testDeepStack() {
    try {
      final int DEPTH = 100000;
      final TermList result = makeList(DEPTH);
      assertNotNull(result);
      assertTrue(checkList(DEPTH, result));
    }
    catch (Exception ex) {
      ex.printStackTrace();
      fail();
    }
  }
}