compile error for parsing a string on vc2005

[pop.atry@…]

#include <string>
#include <boost/spirit/core.hpp>
extern std::string s;
extern boost::spirit::rule<> r;
void compile_failed() {
  boost::spirit::parse(s.begin(), s.end(), r);
}
/**/

This is the error message the compiler reported:

1>parse.cpp
1>c:\documents and settings\yangbo\桌面\work\research\boost\boost\spirit\core\non_terminal\impl\rule.ipp(190) : error C2664: “boost::spirit::impl::abstract_parser<ScannerT,AttrT>::do_parse_virtual”: 不能将参数 1 从“const boost::spirit::scanner<IteratorT,PoliciesT>”转换为“const boost::spirit::scanner<> &”
1>        with
1>        [
1>            ScannerT=boost::spirit::scanner<>,
1>            AttrT=boost::spirit::nil_t
1>        ]
1>        and
1>        [
1>            IteratorT=std::_String_iterator<char,std::char_traits<char>,std::allocator<char>>,
1>            PoliciesT=boost::spirit::scanner_policies<>
1>        ]
1>        原因如下: 无法从“const boost::spirit::scanner<IteratorT,PoliciesT>”转换为“const boost::spirit::scanner<>”
1>        with
1>        [
1>            IteratorT=std::_String_iterator<char,std::char_traits<char>,std::allocator<char>>,
1>            PoliciesT=boost::spirit::scanner_policies<>
1>        ]
1>        没有可用于执行该转换的用户定义的转换运算符，或者无法调用该运算符
1>        c:\documents and settings\yangbo\桌面\work\research\boost\boost\spirit\core\non_terminal\impl\rule.ipp(172): 参见对正在编译的函数 模板 实例化“boost::spirit::match<boost::spirit::nil_t> boost::spirit::impl::rule_base<DerivedT,EmbedT,T0,T1,T2>::parse_main<ScannerT>(const ScannerT &) const”的引用
1>        with
1>        [
1>            DerivedT=boost::spirit::rule<>,
1>            EmbedT=const boost::spirit::rule<> &,
1>            T0=boost::spirit::nil_t,
1>            T1=boost::spirit::nil_t,
1>            T2=boost::spirit::nil_t,
1>            ScannerT=boost::spirit::scanner<std::_String_iterator<char,std::char_traits<char>,std::allocator<char>>,boost::spirit::scanner_policies<>>
1>        ]
1>        c:\documents and settings\yangbo\桌面\work\research\boost\boost\spirit\core\impl\parser.ipp(28): 参见对正在编译的函数 模板 实例化“boost::spirit::match<boost::spirit::nil_t> boost::spirit::impl::rule_base<DerivedT,EmbedT,T0,T1,T2>::parse<boost::spirit::scanner<IteratorT,PoliciesT>>(const ScannerT &) const”的引用
1>        with
1>        [
1>            DerivedT=boost::spirit::rule<>,
1>            EmbedT=const boost::spirit::rule<> &,
1>            T0=boost::spirit::nil_t,
1>            T1=boost::spirit::nil_t,
1>            T2=boost::spirit::nil_t,
1>            IteratorT=std::_String_iterator<char,std::char_traits<char>,std::allocator<char>>,
1>            PoliciesT=boost::spirit::scanner_policies<>,
1>            ScannerT=boost::spirit::scanner<std::_String_iterator<char,std::char_traits<char>,std::allocator<char>>,boost::spirit::scanner_policies<>>
1>        ]
1>        c:\documents and settings\yangbo\桌面\work\research\http_client\parse.cpp(6): 参见对正在编译的函数 模板 实例化“boost::spirit::parse_info<IteratorT> boost::spirit::parse<std::_String_iterator<_Elem,_Traits,_Alloc>,DerivedT>(const IteratorT &,const IteratorT &,const boost::spirit::parser<DerivedT> &)”的引用
1>        with
1>        [
1>            IteratorT=std::_String_iterator<char,std::char_traits<char>,std::allocator<char>>,
1>            _Elem=char,
1>            _Traits=std::char_traits<char>,
1>            _Alloc=std::allocator<char>,
1>            DerivedT=boost::spirit::rule<>
1>        ]

[anonymous]

Scanner incompatibility. See "The Scanner and Parsing" section. Try:

extern boost::spirit::rule<boost::spirit::scanner<std::string::iterator> > r;

[Joel de Guzman]

This is not a bug. See comment above.

[pop.atry@…]

OK, but why does rule need know the iterator type, why not specify the iterator type when parsing?

[Joel de Guzman]

The proper forum to discuss these issues is the Spirit mailing list: ​https://lists.sourceforge.net/lists/listinfo/spirit-general

Anyway, this is also discussed in the docs. IIRC, the FAQ also mentions the reasons.