使用迭代器解析Boost :: Spirit Grammars(Using Iterator parsing with Boost::Spirit Grammars)

使用迭代器解析Boost :: Spirit Grammars(Using Iterator parsing with Boost::Spirit Grammars)

当我尝试使用迭代器形式解析Spirit语法时，我得到一个参数，将迭代器类型的转换错误传递给const char *。 我该如何解决？

有一些限制。 我在大输入上使用迭代器适配器，因此转换为C样式字符串是不可行的。

以下是演示此问题的示例代码：

#include <boost/spirit/core.hpp> #include <boost/spirit/iterator/file_iterator.hpp> #include <vector> #include <string> using std; using boost::spirit; struct ex : public grammar<route_grammar> { template <typename ScannerT> struct defintion { definition(ex const& self) { expression = real_p; } rule<ScannerT> expression; rule<ScannerT> const& start() const { return expression; } }; int main() { file_iterator<char> first; file_iterator<char> last = first.make_end(); ex ex_p; parse_info<file_iterator<char> > info = parse(first, last, ex_p, space_p); return 0; }

此代码断开：错误：无法将const boost::spirit::file_iterator<char_t, boost::spirit::fileiter_impl::mmap_file_iterator<char_t> >转换为参数传递中的const char*

When I attempt to use the iterator form of parsing for a Spirit grammar I get a argument passing conversion error from the iterator type to const char*. How do I fix this?

There are some restrictions. I'm using an iterator adapter on large inputs, so it is not feasible for me to convert to a C style string.

Here is sample code demonstrating the issue:

#include <boost/spirit/core.hpp> #include <boost/spirit/iterator/file_iterator.hpp> #include <vector> #include <string> using std; using boost::spirit; struct ex : public grammar<route_grammar> { template <typename ScannerT> struct defintion { definition(ex const& self) { expression = real_p; } rule<ScannerT> expression; rule<ScannerT> const& start() const { return expression; } }; int main() { file_iterator<char> first; file_iterator<char> last = first.make_end(); ex ex_p; parse_info<file_iterator<char> > info = parse(first, last, ex_p, space_p); return 0; }

This code breaks with: error: cannot convert const boost::spirit::file_iterator<char_t, boost::spirit::fileiter_impl::mmap_file_iterator<char_t> > to const char* in argument passing

最满意答案

很难从代码中看出已发布，因为它包含一些基本错误。 纠正这些后，它在我的机器上编译很好（使用MSVC ++ 7.1）：

#include <boost/spirit/core.hpp> #include <vector> #include <string> using namespace std; using namespace boost::spirit; struct ex : public grammar<ex> { template <typename ScannerT> struct definition { definition(ex const& self) { expression = real_p; } rule<ScannerT> expression; rule<ScannerT> const& start() const { return expression; } }; }; int main() { vector<char> v; v.push_back('3'); v.push_back('.'); v.push_back('2'); ex ex_p; parse_info<vector<char>::iterator> info = parse(v.begin(), v.end(), ex_p, space_p); return 0; }

Hard to tell from the code as posted, since it contains a few basic errors. After correction of these, it compiles fine on my machine (with MSVC++7.1):

#include <boost/spirit/core.hpp> #include <vector> #include <string> using namespace std; using namespace boost::spirit; struct ex : public grammar<ex> { template <typename ScannerT> struct definition { definition(ex const& self) { expression = real_p; } rule<ScannerT> expression; rule<ScannerT> const& start() const { return expression; } }; }; int main() { vector<char> v; v.push_back('3'); v.push_back('.'); v.push_back('2'); ex ex_p; parse_info<vector<char>::iterator> info = parse(v.begin(), v.end(), ex_p, space_p); return 0; }