PHP调用WebService接口，谁给看下这段代码是什么意思呢？

Question

$document=$proxy->document;
echo <<<SoapDocument
<?xml version=”1.0″ encoding=”GB2312″?>
<SOAP-ENV:Envelope SOAP-ENV:encodingStyle=”http://schemas.xmlsoap.org/soap/encoding/” xmlns:SOAP-ENV=”http://schemas.xmlsoap.org/soap/envelope/” xmlns:xsd=”http://www.w3.org/2001/XMLSchema” xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns:SOAP-ENC=”http://schemas.xmlsoap.org/soap/encoding/” xmlns:si=”http://soapinterop.org/xsd“>
<SOAP-ENV:Body>
$document
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
SoapDocument;
顺便问一下在PHP中出现下面这种形式？会冲突吗？该怎么解决？<?php
<??>
?>

Answer 1

把被 SoapDocument 括起的内容作为一个字符串输出在启用了短标记的情况下
<?php
<?
 
?>
?>
将产生语法错误！