OperatorTest.java

package com.igormaznitsa.prol.test;

import com.igormaznitsa.prol.data.Term;
import com.igormaznitsa.prol.data.TermStruct;
import com.igormaznitsa.prol.data.Var;
import com.igormaznitsa.prol.logic.Goal;
import com.igormaznitsa.prol.logic.PreparedGoal;
import com.igormaznitsa.prol.logic.ProlContext;
import com.igormaznitsa.prol.parser.ProlConsult;
import junit.framework.TestCase;
import org.junit.Test;

public class OperatorTest extends TestCase {

  @Test
  public void testOperatorDefs() {
    try {
      final ProlContext context = new ProlContext("Operator_test");
      final ProlConsult consult = new ProlConsult(":-op(800,xfx,'<===>'). :-op(700,xfy,'v'). :-op(600,xfy,'&'). :-op(500,fy,'~'). moon <===> earth.", context);
      consult.consult();

      PreparedGoal prepGoal = new PreparedGoal("~(xxx & yyy) <===> ~xxx v ~yyy.", context);
      TermStruct root = (TermStruct) prepGoal.getParsedGoal();

      assertEquals(root.getText(), "<===>");
      assertEquals(root.getArity(), 2);

      TermStruct lefttree = (TermStruct) root.getElement(0);
      TermStruct righttree = (TermStruct) root.getElement(1);

      assertEquals(lefttree.getText(), "~");
      assertEquals(lefttree.getArity(), 1);
      assertEquals(righttree.getText(), "v");
      assertEquals(righttree.getArity(), 2);

      final TermStruct prevrighttree = righttree;

      lefttree = (TermStruct) lefttree.getElement(0);
      righttree = (TermStruct) righttree.getElement(0);

      assertEquals(lefttree.getText(), "&");
      assertEquals(lefttree.getArity(), 2);
      assertEquals(lefttree.getElement(0).getTermType(), Term.TYPE_ATOM);
      assertEquals(lefttree.getElement(1).getTermType(), Term.TYPE_ATOM);
      assertEquals(lefttree.getElement(0).getText(), "xxx");
      assertEquals(lefttree.getElement(1).getText(), "yyy");

      lefttree = (TermStruct) prevrighttree.getElement(0);
      righttree = (TermStruct) prevrighttree.getElement(1);

      assertEquals(lefttree.getArity(), 1);
      assertEquals(lefttree.getText(), "~");
      assertEquals(righttree.getArity(), 1);
      assertEquals(righttree.getText(), "~");
      assertEquals(lefttree.getElement(0).getTermType(), Term.TYPE_ATOM);
      assertEquals(lefttree.getElement(0).getText(), "xxx");
      assertEquals(righttree.getElement(0).getTermType(), Term.TYPE_ATOM);
      assertEquals(righttree.getElement(0).getText(), "yyy");

      final PreparedGoal prepGoal2 = new PreparedGoal("moon <===> X.", context);
      int solvecounter = 0;
      Term result = null;
      final Goal gl = prepGoal2.getNonparametrizedGoalInstance();
      String text = null;
      while (true) {
        final Term curresult = gl.solve();
        if (curresult == null) {
          break;
        }

        text = gl.getVarForName("X").getValue().getText();

        result = curresult;
        solvecounter++;
      }

      assertEquals(solvecounter, 1);
      assertEquals(text, "earth");

    }
    catch (Exception ex) {
      ex.printStackTrace();
      fail(ex.toString());
    }
  }
}