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/*******************************************************************************
* Copyright (c) 2009 Luaj.org. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* 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.
*
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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package nl.weeaboo.lua2.lib;

import static nl.weeaboo.lua2.vm.LuaConstants.NONE;

import nl.weeaboo.lua2.io.LuaSerializable;
import nl.weeaboo.lua2.vm.LuaValue;
import nl.weeaboo.lua2.vm.Varargs;

/**
 * Abstract base class for Java function implementations that takes varaiable arguments and returns multiple
 * return values.
 * 
 * Subclasses need only implement {@link LuaValue#invoke(Varargs)} to complete this class, simplifying
 * development. All other uses of {@link #call(LuaValue)}, {@link #invoke()},etc, are routed through this
 * method by this class, converting arguments to {@link Varargs} and dropping or extending return values with
 * {@code nil} values as required.
 * 

 * If between one and three arguments are required, and only one return value is returned,
 * {@link ZeroArgFunction}, {@link OneArgFunction}, {@link TwoArgFunction}, or {@link ThreeArgFunction}.
 * 
 * See {@link LibFunction} for more information on implementation libraries and library functions.
 *
 * @see #invoke(Varargs)
 * @see LibFunction
 * @see ZeroArgFunction
 * @see OneArgFunction
 * @see TwoArgFunction
 * @see ThreeArgFunction
 */
@LuaSerializable
public abstract class VarArgFunction extends LibFunction {

    private static final long serialVersionUID = -2534602021495342749L;

    public VarArgFunction() {
    }

    public VarArgFunction(LuaValue env) {
        this.env = env;
    }

    @Override
    public LuaValue call() {
        return invoke(NONE).arg1();
    }

    @Override
    public final LuaValue call(LuaValue arg) {
        return invoke(arg).arg1();
    }

    @Override
    public final LuaValue call(LuaValue arg1, LuaValue arg2) {
        return invoke(varargsOf(arg1, arg2)).arg1();
    }

    @Override
    public final LuaValue call(LuaValue arg1, LuaValue arg2, LuaValue arg3) {
        return invoke(varargsOf(arg1, arg2, arg3)).arg1();
    }

}