xml - 获取没有特定祖先xml xpath的节点

Question

我在相当复杂的xpath中苦苦挣扎了几天，我无法制定它。
我有一个来自c ++的语法树，例如语言解析器，我想进行xpath查询，该查询选择所有不在函数名称中的名称。

具体来说，我有这样的xml文件

（整个xml文档位于问题的最后，相当大，我在此处粘贴了文档结构的简单概述）
有四种节点类型
a-此元素包含一个节点
b-包含节点的信息（例如“ CALL_EXPRESSION”）
c-包含实际文本（例如“ printf”，变量名...）
d-包含当前节点的后代（a元素）

CALL_EXPRESSION  DOT_EXPRESSION    NAME_EXPRESSION      NAME    NAME_EXPRESSION      NAME  PARAMS    NAME_EXPRESSION      NAMECALL_EXPRESSION  NAME_EXPRESSION    NAME  PARAMS    NAME_EXPRESSION      NAMEASSIGNMENT_EXPRESSION  NAME_EXPRESSION    NAME  NAME_EXPRESSION    NAME

I would like to formulate Xpath query, that would select all NAMEs that are not descendats of CALL_EXPRESSION/*[1]. (This means i would like to select all variables and not the function names).

To select all the function names I can use Xpath like this

//a[b="CALL_EXPRESSION"]/d/a[1]

no problem here. Now, if I would like to select all nodes that are not descendats of this nodes. I would use not(ancestor::X).

But here goes the problem, if I formulate the Xpath expression like this:

//*[b="NAME"][not(ancestor::a[b="CALL_EXPRESSION"]/d/a[1])]

it selects only nodes, that don't have a that has child b="CALL_EXPRESSION" at all. In our example, it selects only NAME from the ASSIGNMENT_EXPRESSION subtree.

I suspected, that the problem is, that ancestor:: takes only the first element (in our case a[b="CALL_EXPRESSION"]) and restricts according to its predicate and further / are discarded. So i modified the xpath query like this:

//*[b="NAME"][not(ancestor::a[../../b="CALL_EXPRESSION" and position()=1])]

This seems to work only on the simpler CALL_EXPRESSION (without the DOT_EXPRESSION). I suspected, that the path in [] might be relative only to current node, not to the potential ancestors. But when I used the query

//*[b="NAME"][not(ancestor::a[b="CALL_EXPRESSION"])]

it worked as one would assume (all NAMEs what don't have ancestor CALL_EXPRESSION were selected).

Is there any way to formulate the query I need? And why don't the queries work?

Thanks in advance :)

The XML

<a>
 <b>CALL_EXPRESSION</b>
 <c>object.method(a)</c>
 <d>
   <a>
     <b>DOT_EXPRESSION</b>
     <c>object.method</c>
     <d>
       <a>
         <b>NAME_EXPRESSION</b>
         <c>object</c>
         <d>
           <a>
             <b>NAME</b>
             <c>object</c>
             <d>
             </d>
           </a>
         </d>
       </a>
       <a>
         <b>NAME_EXPRESSION</b>
         <c>method</c>
         <d>
           <a>
             <b>NAME</b>
             <c>method</c>
             <d>
             </d>
           </a>
         </d>
       </a>
     </d>
   </a>
   <a>
     <b>PARAMS</b>
     <c>(a)</c>
     <d>
       <a>
         <b>NAME_EXPRESSION</b>
         <c>a</c>
         <d>
           <a>
             <b>NAME</b>
             <c>a</c>
             <d>
             </d>
           </a>
         </d>
       </a>
     </d>
   </a>
 </d>
</a>

<a>
 <b>CALL_EXPRESSION</b>
 <c>puts(b)</c>
 <d>
   <a>
     <b>NAME_EXPRESSION</b>
     <c>puts</c>
     <d>
       <a>
         <b>NAME</b>
         <c>puts</c>
         <d>
         </d>
       </a>
     </d>
   </a>
   <a>
     <b>PARAMS</b>
     <c>(b)</c>
     <d>
       <a>
         <b>NAME_EXPRESSION</b>
         <c>b</c>
         <d>
           <a>
             <b>NAME</b>
             <c>b</c>
             <d>
             </d>
           </a>
         </d>
       </a>
     </d>
   </a>
 </d>
</a>

<a>
 <b>ASSIGNMENT_EXPRESSION</b>
 <c>c=d;</c>
 <d>
   <a>
     <b>NAME_EXPRESSION</b>
     <c>c</c>
     <d>
       <a>
         <b>NAME</b>
         <c>c</c>
         <d>
         </d>
       </a>
     </d>
   </a>
   <a>
     <b>NAME_EXPRESSION</b>
     <c>d</c>
     <d>
       <a>
         <b>NAME</b>
         <c>d</c>
         <d>
         </d>
       </a>
     </d>
   </a>
 </d>
</a>

Answer 1

您没有说这是XPath 1.0还是2.0。在XPath 2.0中，可以使用except运算符：例如

//* except //x//*

选择所有没有x的元素作为祖先。

还可以使用等效项在XPath 1.0中模拟except运算符

E1 except E2 ==> E1[count(.|E2)!=count(E2)]

（但要注意评估E2的环境）。