PHP，变量里含有变量！

		$query=new IQuery('msg_template');		$query->limit="1";		$query->where="id = 4";		$arra=$query->find();		$mtitle=$arra[0]['title'];		$mopen=$arra[0]['open'];		$mcontent=$arra[0]['content'];		$madmin_open=$arra[0]['admin_open'];		if($madmin_open==1){		$madmin_email=$arra[0]['admin_email'];		}     //$mcontent = "dear：{".$user['username']."}   你购买的商品：{".$goods_name."}，订单号{".$goods_no."}已下单成功，由于此商品近期销售火爆，请及时付款！";	if($mopen==1){						$smtp  = new SendMail();		    $error = $smtp->getError();			$smtp->send($email,$mtitle,$mcontent,$madmin_email);	}

//模拟从数据库中读出的数据$mcontent =<<< 'TXT'dear：{$user['username']}   你购买的商品：{$goods_name}，订单号{$goods_no}已下单成功，由于此商品近期销售火爆，请及时付款！TXT;//涉及的变量需自行保证存在$user['username'] = 'body';$goods_name = 'xxx';$goods_no = '123';//方案一 不过有不少人恐惧 eval$mcontent = eval("return \"$mcontent\";");echo $mcontent;//方案二 动态创建函数，格式有点绕人$f = create_function('$user,$goods_name,$goods_no', "return \"$mcontent\";");$mcontent = $f($user, $goods_name, $goods_no);echo $mcontent;//或$f = create_function('$user,$goods_name,$goods_no', 'return "' . $mcontent . '";');$mcontent = $f($user, $goods_name, $goods_no);echo $mcontent;//方案三 模板变量替换，这是解释型模板引擎的做法$mcontent = preg_replace('/{\$[^}]+}/e', '$1', $mcontent);echo $mcontent;