PHPオブジェクトのパラメータが不明な場合の対処方法

<?php
function uncertainParam() {
    $numargs = func_num_args();    //获得传入的所有参数的个数
    echo "参数个数: $numargs\n";  
    $args = func_get_args();       //获得传入的所有参数的数组 
    foreach($args as $key=>$value){
        echo &#39;<BR><BR>&#39;.func_get_arg($key);   //获取单个参数的值
        echo &#39;<BR>&#39;.$value;        //单个参数的值
    }
    var_export($args);  
}   
$parm_fir = &#39;name&#39;;
$parm_sec = &#39;sex&#39;;
uncertainParam($parm_fir, $parm_sec);

<?php
function mosaic($var1, $var2, $var3=&#39;c&#39;, $var4=&#39;d&#39;){
     return $var1+$var2+$var3+$var4;
}
$parm_fir = &#39;a&#39;;
$parm_sec = &#39;b&#39;;
$parm_three = &#39;c&#39;;
$parm_four = &#39;d&#39;;
echo mosaic($parm_fir , $parm_sec);    //输出&#39;ab&#39;
echo mosaic($parm_fir, $parm_sec, $parm_three); //输出&#39;abc&#39;
echo mosaic($parm_fir, $parm_sec, $parm_three, $parm_four);//输出&#39;abcd&#39;
echo mosaic($parm_fir);      //出错:必须给出第二个必填参数
echo mosaic($parm_fir, $parm_sec, , $parm_three);//出错:不能跳过任何一个可选参数而给出列表中后面的可选参数
?>