扩展使用ReflectionFunction的建议，您可以使用类似以下的内容：

$func = new ReflectionFunction('myfunction');
$filename = $func->getFileName();
$start_line = $func->getStartLine() - 1; // it's actually - 1, otherwise you wont get the function() block
$end_line = $func->getEndLine();
$length = $end_line - $start_line;

$source = file($filename);
$body = implode("", array_slice($source, $start_line, $length));
print_r($body);