ConstExpr.java

/*
 * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package com.caucho.quercus.expr;

import com.caucho.quercus.Location;
import com.caucho.quercus.env.Env;
import com.caucho.quercus.env.StringBuilderValue;
import com.caucho.quercus.env.Value;

/**
 * Represents a PHP constant expression.
 */
public class ConstExpr extends Expr {
  protected final String _var;

  public ConstExpr(Location location, String var)
  {
    super(location);
    _var = var;
  }

  public ConstExpr(String var)
  {
    this(Location.UNKNOWN, var);// acceptable, for compiled code
  }

  /**
   * Returns the variable.
   */
  public String getVar()
  {
    return _var;
  }

  /**
   * Returns true for literal
   */
  public Value evalConstant()
  {
    return new StringBuilderValue(_var);
  }

  /**
   * Evaluates the expression.
   *
   * @param env the calling environment.
   *
   * @return the expression value.
   */
  public Value eval(Env env)
  {
    return env.getConstant(_var);
  }

  public String toString()
  {
    return _var;
  }
}