Boost.Spirit.Qi - 规则开头的错误
如何在规则开始时检测错误？例如，请考虑 Mini XML示例包含在文档中。如果我给解析器提供像：
How would I detect an error at the start of a rule? For example, consider the Mini XML example included in the docs. If I feed the parser something like:
<element>this is an error<element>
然后我得到：
错误！期望在这里：
Error! Expecting here: ""
错误！期望在这里：
解析失败。
然后考虑送入：
element>this is an error</element>
我得到非常通用，不太有用：
And I get the very generic and not so useful:
解析失败。
Parsing failed.
如何修改规则以报告错误
How could I modify the rule to report the error in an informative way?
您需要在文档根级别
其他邮件是由失败的期望点产生的。您需要在开始时添加额外的期望点。我会这样做：
The other messages are generated by failed expectation points. You'll want an extra expectation point at the start. I'd do this:
- 将旧
xml重命名为element -
创建一个新的
xml规则， ：
- rename old
xmlrule toelement create a new
xmlrule that has the element at an expectation point:
xml = qi::eps > element;
[不要更改任何内容]
[Don't change anything else]
利润！
profit!
>输出变为：
The output becomes:
Error! Expecting <element> here: "element>this is a test</element>
"
-------------------------
Parsing failed
-------------------------
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