package org.djutils.eval;
   
   import java.util.HashMap;
   import java.util.Map;
   
   import org.djunits.value.vdouble.scalar.Position;
   import org.djunits.value.vdouble.scalar.base.DoubleScalar;
   
   /**
   * Calculator.java. Demonstrates use of the Eval class.
   * <p>
   * Copyright (c) 2023-2024 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
   * for project information <a href="https://djutils.org" target="_blank"> https://djutils.org</a>. The DJUTILS project is
   * distributed under a three-clause BSD-style license, which can be found at
   * <a href="https://djutils.org/docs/license.html" target="_blank"> https://djutils.org/docs/license.html</a>.
   * </p>
   * @author <a href="https://www.tudelft.nl/pknoppers">Peter Knoppers</a>
   */
  public class Calculator
  {
      /**
       * Demonstrate the Eval class. Program entry point.
       * @param args String ...; the command line arguments
       */
      public static void main(final String... args)
      {
          doEval("3[kg.ms-2]");
          doEval("23.45*10");
          doEval(" 23.45 * 10 ");
          doEval("PI()*AVOGADRO()");
          doEval("PI()");
          doEval("PI()/PI()");
          doEval("CURRENTTIME()");
          doEval("PHI()");
          System.out.println();
          doEval("NEUTRONMASS()-ELECTRONMASS()");
          doEval("NEUTRONMASS()-PI()");
          doEval("12 [ms-1] / 123[/s]");
          Map<String, DoubleScalar<?,?>> valuePool = new HashMap<>();
          valuePool.put("position", Position.valueOf("100 m")); // Absolute
          doEval("position-10[m]", new RetrieveValue() {
  
              @Override
              public DoubleScalar<?, ?> lookup(final String name)
              {
                  return valuePool.get(name);
              }});
          doEval("position+10[m]", new RetrieveValue() {
  
              @Override
              public DoubleScalar<?, ?> lookup(final String name)
              {
                  return valuePool.get(name);
              }});
          doEval("position-position", new RetrieveValue() {
  
              @Override
              public DoubleScalar<?, ?> lookup(final String name)
              {
                  return valuePool.get(name);
              }});
          doEval("position+position", new RetrieveValue() {
  
              @Override
              public DoubleScalar<?, ?> lookup(final String name)
              {
                  return valuePool.get(name);
              }});
          doEval("5^3");
          doEval("5<5");
          doEval("!5<5");
          doEval("12 [m/s] > 7 [m]");
          doEval("TRUE()");
          doEval("FALSE()");
          doEval("TRUE()!=5");
          doEval("TRUE()==5");
          doEval("FALSE()==5");
          doEval("(2>3)?5:1+100");
          doEval("PHI()");
          doEval("-0==0");//FIXME
          doEval("2^-2");
          doEval("3e+5");
          doEval("12>4?TRUE():(9+5)");
          doEval("3==5!");
          doEval("3[km/h]");
          doEval("5*2[s]/5[s]");
      }
  
      /**
       * Print expression followed by the result.
       * @param expression String; expression to evaluate
       */
      public static void doEval(final String expression)
      {
          doEval(expression, null);
      }
      
      /**
       * Print expression followed by the result.
      * @param expression String; the expression to evaluate
      * @param valuePool RetrieveValue; variable pool
      */
     public static void doEval(final String expression, final RetrieveValue valuePool)
     {
         try
         {
             Object result = new Eval().setRetrieveValue(valuePool).evaluate(expression);
             System.out.println(expression + ": " + result);
         }
         catch (RuntimeException e)
         {
             System.out.println(expression + ": ERROR: "+ e.getMessage());
         }
     }
 }