PHP変数関数の使用状況分析

<?php
function  foo () {
    echo  "In foo()<br />/n" ;
}
function  bar ( $arg  =  &#39;&#39; ) {
    echo  "In bar(); argument was &#39; $arg &#39;.<br />/n" ;
}
// 使用 echo 的包装函数
function  echoit ( $string )
{
    echo  $string ;
}
$func  =  &#39;foo&#39; ;
$func ();         // This calls foo()
$func  =  &#39;bar&#39; ;
$func ( &#39;test&#39; );   // This calls bar()
$func  =  &#39;echoit&#39; ;
$func ( &#39;test&#39; );   // This calls echoit()
?>

<?php
class  Foo
{
    function  Variable ()
    {
         $name  =  &#39;Bar&#39; ;
         $this -> $name ();  // This calls the Bar() method
     }
    function  Bar ()
    {
        echo  "This is Bar" ;
    }
}
$foo  = new  Foo ();
$funcname  =  "Variable" ;
$foo -> $funcname ();    // This calls $foo->Variable()
?>