Boost Spirit x3解析为具有单个字段的结构 [英] Boost Spirit x3 parsing into a struct with single field
问题描述
我一直在研究提振精神的例子，并遇到了以下问题.(我认为它在某些地方像代码中的错误一样被描述，但是我可能是错的)
Im keep invistigate boost spirit examples, and collided with the following problem. (i think it was described somwhere like a bug in the code, but i may be wrong)
简而言之:当尝试解析具有从x3 :: variant继承的单个文件类型的结构时，解析器没有生成.
Simply: Parser didn build when try to pars into a struct with a single filed of type inherited from x3::variant.
这是代码的一部分
struct operand : x3::variant<
nil
, unsigned int
, std::string
, x3::forward_ast<expression>
>
{
using base_type::base_type;
using base_type::operator=;
};
struct assign_return
{
char sign;
operand var;
};
我将其解析为以下内容(当然，所有需要正确定义的内容)
which i parse as folows (of cource all it needed define correctly)
auto const areturn_def =
lexeme["return" >> !(alnum | '_')] >> char_(':') >> expression >> ';';
此代码正常工作
但是，如果我不想解析':'并按照(按照惯例，我会在此结构的BOOST_FUSION_ADAPT_STRUCT中进行更改)
but if i dont wanna parse ':' and chaged everything according with (ofcource i do changes in BOOST_FUSION_ADAPT_STRUCT for this struct)
struct assign_return
{
operand var;
};
auto const areturn_def =
lexeme["return" >> !(alnum | '_')] >> expression >> ';';
此代码未出现以下错误:
This code didnt build up with the foollowing error:
C:\Program Files\boost\boost\boost\spirit\home\x3\nonterminal\rule.hpp:113: undefined reference to `bool client::parser::parse_rule<__gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::spirit::x3::context<boost::spirit::x3::skipper_tag, boost::spirit::x3::char_class<boost::spirit::char_encoding::ascii, boost::spirit::x3::space_tag> const, boost::spirit::x3::unused_type>, client::ast::assign_return>(boost::spirit::x3::rule<client::parser::expression_class, client::ast::expression, false>, __gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >&, __gnu_cxx::__normal_iterator<char const*, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > > const&, boost::spirit::x3::context<boost::spirit::x3::skipper_tag, boost::spirit::x3::char_class<boost::spirit::char_encoding::ascii, boost::spirit::x3::space_tag> const, boost::spirit::x3::unused_type> const&, client::ast::assign_return&)'
如果我们仔细查看错误代码并提及错误功能
If we look carefully at the error code and function it mention
template <typename Iterator, typename Context, typename Attribute_>
bool parse(Iterator& first, Iterator const& last
, Context const& context, unused_type, Attribute_& attr) const
我们可以看到，模板参数正确，但是参数列表:
We could see, that template parameters are correct, but argument list:
(rule, iterator, iterator, context, Attribute)
这似乎是未定义引用的问题，但是如何解决?
It seems like a problem of undefined reference, but how?
感谢您的帮助！
推荐答案
是的.看起来与单元素序列无关.链接器错误通常是:)
Yeah. This looks like unrelated to single-element sequences. Linker errors usually are :)
您可能可以使用演示的技术
You could probably employ the techniques demonstrated
查找罪魁祸首.如果您发布完整，最少的有效"示例，我们可以为您提供帮助.
To find the culprit. If you post a full, minimal, "working" example we can help.
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