//
// FormulaVar.java
//

/*
VisAD system for interactive analysis and visualization of numerical
data.  Copyright (C) 1996 - 2017 Bill Hibbard, Curtis Rueden, Tom
Rink, Dave Glowacki, Steve Emmerson, Tom Whittaker, Don Murray, and
Tommy Jasmin.

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA
*/

package visad.formula;

import java.lang.reflect.InvocationTargetException;
import java.rmi.RemoteException;
import java.util.*;
import visad.*;

/** Represents a variable.
 */
public class FormulaVar extends ActionImpl {

  /** for testing purposes */
  public static boolean DEBUG = false;

  /** constant tag */
  public static RealType CONSTANT =
    RealType.getRealType("visad/formula/constant");

  /** associated FormulaManager object */
  private FormulaManager fm;

  /** name of this variable */
  String name;

  /** formula associated with this variable, if any */
  private String formula;

  /** formula in postfix notation, if it has been converted */
  private Postfix postfix;

  /** reference of this variable */
  private ThingReference tref;

  /** list of errors that have occurred during computation, in String form */
  private Vector errors = new Vector();

  /** for synchronization */
  private Object Lock = new Object();

  /** whether the formula is currently being computed */
  private boolean computing = false;

  /** constructor without specified ThingReference */
  FormulaVar(String n, FormulaManager f) throws VisADException {
    this(n, f, null);
  }

  /** constructor with specified ThingReference */
  FormulaVar(String n, FormulaManager f, ThingReference t)
    throws VisADException
  {
    super(n);
    fm = f;
    name = n;
    tref = (t == null) ? new ThingReferenceImpl(name) : t;
    for (int i=0; i= 0) {
        throw new FormulaException("variable names cannot contain operators");
      }
    }
    for (int i=0; i= 0) {
        throw new FormulaException("variable names cannot contain operators");
      }
    }
  }

  /** vector of variables on which this one depends */
  private Vector depend = new Vector();

  /** vector of variables that require this variable (depend on it) */
  private Vector required = new Vector();

  /** return whether any other variables depend on this one */
  boolean othersDepend() {
    return !required.isEmpty();
  }

  /** return whether this variable depends on v */
  boolean isDependentOn(FormulaVar v) {
    if (v == this || depend.contains(v)) return true;
    for (int i=0; i 0) o = new Object[num];
          else o = null;
          boolean eflag = false;
          for (int j=num-1; j>=0; j--) {
            o[j] = popStack(stack);
            if (o[j] == null) eflag = true;
          }
          if (!eflag) {
            for (int j=0; j=0; j--) {
            o[j] = popStack(stack);
            if (o[j] == null) eflag = true;
          }
          if (!eflag) {
            for (int j=0; j