headfunction.java

来自「java写的多功能文件编辑器」· Java 代码 · 共 50 行

/*
 * HeadFunction.java - get a string head
 * Copyright (C) 2000 Romain Guy
 * [e-mail]
 * http://www.jext.org
 *
 * This program 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 any later version.
 *
 * This program 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 PURHeadE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package org.jext.dawn.string;

import org.jext.dawn.*;

/**
 * Get first char of a string.<br>
 * Usage:<br>
 * <code>string head</code>
 * @author Romain Guy
 */

public class HeadFunction extends Function
{
  public HeadFunction()
  {
    super("head");
  }

  public void invoke(DawnParser parser) throws DawnRuntimeException
  {
    parser.checkEmpty(this);
    String str = parser.popString();
    if (str.length() != 0)
      parser.pushString(new StringBuffer().append(str.charAt(0)).toString());
  }
}

// End of HeadFunction.java