content: /*******************************************************************************
  * Copyright (c) 2009 Luaj.org. All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  * 
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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  * THE SOFTWARE.
  ******************************************************************************/
  package org.luaj.vm2.lib;
  
  import org.luaj.vm2.LuaValue;
  import org.luaj.vm2.Varargs;
  
  /** Abstract base class for Java function implementations that take two arguments and 
   * return one value. 
   * <p>
   * Subclasses need only implement {@link LuaValue#call(LuaValue,LuaValue,LuaValue)} to complete this class, 
   * simplifying development.  
   * All other uses of {@link #call()}, {@link #invoke(Varargs)},etc, 
   * are routed through this method by this class, 
   * dropping or extending arguments with {@code nil} values as required.
   * <p>
   * If more or less than three arguments are required,  
   * or variable argument or variable return values, 
   * then use one of the related function
   * {@link ZeroArgFunction}, {@link OneArgFunction}, {@link TwoArgFunction}, or {@link VarArgFunction}.
   * <p>
   * See {@link LibFunction} for more information on implementation libraries and library functions.
   * @see #call(LuaValue,LuaValue,LuaValue)
   * @see LibFunction
   * @see ZeroArgFunction
   * @see OneArgFunction
   * @see TwoArgFunction
   * @see VarArgFunction
   */
  abstract public class ThreeArgFunction extends LibFunction {
  
  	abstract public LuaValue call(LuaValue arg1, LuaValue arg2, LuaValue arg3);
  	
  	/** Default constructor */
  	public ThreeArgFunction() {
  	}
  	
  	public final LuaValue call() {
  		return call(NIL, NIL, NIL);
  	}
  
  	public final LuaValue call(LuaValue arg) {
  		return call(arg, NIL, NIL);
  	}
  
  	public LuaValue call(LuaValue arg1, LuaValue arg2) {
  		return call(arg1, arg2, NIL);
  	}
  	
  	public Varargs invoke(Varargs varargs) {
  		return call(varargs.arg1(),varargs.arg(2),varargs.arg(3));
  	}
  	
  } 
  