Spirit 无法为单元素结构(或融合序列)分配属性

2021-12-24 00:00:00 c++ boost boost-spirit boost-spirit-qi

我的目标是让我的 qi::grammar 返回一个属性.不过，我在使用 spirit::lexer 时遇到了很大的困难.

My goal is to have my qi::grammar return an attribute. I'm having significant difficulty doing this with a spirit::lexer though.

我希望使用下面给定的语法，如果我用 spirit::qi::parse(begin, end,grammar, output); 调用它，structident 输出 将包含已解析词素的内容.

I'd expect that with the given grammar below, if I called it with spirit::qi::parse(begin, end, grammar, output);, that the struct ident output would have the contents of the parsed lexeme.

错误似乎主要是从这一行流出:start %= lexer.identifier;

The error seems to mostly flow out of this line: start %= lexer.identifier;

  • 提升 1.47.0
  • Mac OS X 10.7.2
  • clang++ 或 g++(下面显示的错误来自 clang++)
g++ -g -c -O0 -Wall -DBOOST_SPIRIT_DEBUG -DBOOST_SPIRIT_LEXERTL_DEBUG -DBOOST_SPIRIT_USE_PHOENIX_V3 -DBOOST_SPIRIT_ACTIONS_ALLOW_ATTR_COMPAT reduced.cpp

源代码

#include <boost/fusion/include/adapt_struct.hpp>

#include <boost/spirit/home/lex.hpp>
#include <boost/spirit/home/lex/lexer/lexertl/lexer.hpp>
#include <boost/spirit/home/qi.hpp>

namespace spirit = boost::spirit;

struct ident {
    std::string value;
};

BOOST_FUSION_ADAPT_STRUCT(ident,
        (std::string, value)
        )

struct my_lexer : spirit::lex::lexer< spirit::lex::lexertl::actor_lexer<> > {
    spirit::lex::token_def<std::string> identifier;
};

struct my_grammar : spirit::qi::grammar<my_lexer::iterator_type, ident()> {
    my_grammar(const my_lexer & lexer) : my_grammar::base_type(start) {
        start %= lexer.identifier;
    }

    spirit::qi::rule<my_lexer::iterator_type, ident()> start;
};

报告了 2 个错误

In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:20:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:38:24: error: no matching constructor for initialization of 'ident'
                attr = Attribute(first, last);
                       ^         ~~~~~~~~~~~
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:94:13: note: in instantiation of member function 'boost::spirit::traits::assign_to_attribute_from_iterators<ident, char const *,
      void>::call' requested here
            call(first, last, attr);
            ^
In file included from ../reduced-example/reduced.cpp:4:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/lexertl/lexer.hpp:20:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/lexertl/token.hpp:530:13: note: in instantiation of function template specialization 'boost::spirit::traits::assign_to<char const *, ident>'
      requested here
            spirit::traits::assign_to(t.value().begin(), t.value().end(), attr);
            ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:20:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:330:59: note: in instantiation of member function 'boost::spirit::traits::assign_to_attribute_from_value<ident,
      boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, void>::call' requested here
            assign_to_attribute_from_value<Attribute, T>::call(val, attr);
                                                          ^
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:353:9: note: in instantiation of function template specialization
      'boost::spirit::traits::detail::assign_to<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, ident>' requested here
        detail::assign_to(val, attr, is_not_wrapped_container());
        ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:106:21: note: in instantiation of function template specialization
      'boost::spirit::traits::assign_to<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, ident>' requested here
                    spirit::traits::assign_to(t, attr);
                    ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:21:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/reference.hpp:16:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/reference.hpp:43:20: note: (skipping 5 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
            return ref.get().parse(first, last, context, skipper, attr);
                   ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/tokenize_and_parse.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/grammar.hpp:18:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/rule.hpp:16:
In file included from /home/wlynch/Boost/1.47.0/include/boost/function.hpp:64:
In file included from /home/wlynch/Boost/1.47.0/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:67:
In file included from /home/wlynch/Boost/1.47.0/include/boost/function/detail/function_iterate.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/function/detail/maybe_include.hpp:33:
/home/wlynch/Boost/1.47.0/include/boost/function/function_template.hpp:1042:5: note: in instantiation of function template specialization 'boost::function4<bool,
      boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>,
      lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > &, boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *,
      boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > const &, boost::spirit::context<boost::fusion::cons<ident &,
      boost::fusion::nil>, boost::fusion::vector0<void> > &, boost::spirit::unused_type const
      &>::function4<boost::spirit::qi::detail::parser_binder<boost::spirit::lex::reference<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> const, unsigned long>, mpl_::bool_<1> > >'
      requested here
    base_type(f)
    ^
/home/wlynch/Boost/1.47.0/include/boost/function/function_template.hpp:1083:5: note: in instantiation of function template specialization 'boost::function<bool
      (boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>,
      lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > &, boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *,
      boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > const &, boost::spirit::context<boost::fusion::cons<ident &,
      boost::fusion::nil>, boost::fusion::vector0<void> > &, boost::spirit::unused_type const
      &)>::function<boost::spirit::qi::detail::parser_binder<boost::spirit::lex::reference<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> const, unsigned long>, mpl_::bool_<1> > >'
      requested here
    self_type(f).swap(*this);
    ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/tokenize_and_parse.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/grammar.hpp:18:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/rule.hpp:182:19: note: in instantiation of function template specialization 'boost::function<bool
      (boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>,
      lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > &, boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *,
      boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > const &, boost::spirit::context<boost::fusion::cons<ident &,
      boost::fusion::nil>, boost::fusion::vector0<void> > &, boost::spirit::unused_type const
      &)>::operator=<boost::spirit::qi::detail::parser_binder<boost::spirit::lex::reference<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> const, unsigned long>, mpl_::bool_<1> > >'
      requested here
            lhs.f = detail::bind_parser<Auto>(
                  ^
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/rule.hpp:230:13: note: in instantiation of function template specialization
      'boost::spirit::qi::rule<boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned
      long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > >, ident (), boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>::define<mpl_::bool_<1>,
      boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> >' requested here
            define<mpl::true_>(r, expr, traits::matches<qi::domain, Expr>());
            ^
../reduced-example/reduced.cpp:23:9: note: in instantiation of function template specialization 'boost::spirit::qi::operator%=<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> >'
      requested here
                start %= lexer.identifier;
                      ^
../reduced-example/reduced.cpp:9:8: note: candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 2 were provided
struct ident {
       ^
../reduced-example/reduced.cpp:9:8: note: candidate constructor (the implicit copy constructor) not viable: requires 1 argument, but 2 were provided
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:17:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/parser.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/domain.hpp:18:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/support/context.hpp:18:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/support/nonterminal/expand_arg.hpp:20:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/support/string_traits.hpp:16:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/support/container.hpp:368:22: error: no member named 'empty' in 'ident'
            return c.empty();
                   ~ ^
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/support/container.hpp:375:47: note: in instantiation of member function 'boost::spirit::traits::is_empty_container<ident, void>::call' requested here
        return is_empty_container<Container>::call(c);
                                              ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:20:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:37:17: note: in instantiation of function template specialization 'boost::spirit::traits::is_empty<ident>' requested here
            if (traits::is_empty(attr))
                ^
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:94:13: note: in instantiation of member function 'boost::spirit::traits::assign_to_attribute_from_iterators<ident, char const *,
      void>::call' requested here
            call(first, last, attr);
            ^
In file included from ../reduced-example/reduced.cpp:4:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/lexertl/lexer.hpp:20:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/lexertl/token.hpp:530:13: note: in instantiation of function template specialization 'boost::spirit::traits::assign_to<char const *, ident>'
      requested here
            spirit::traits::assign_to(t.value().begin(), t.value().end(), attr);
            ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:13:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/lexer/token_def.hpp:20:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:330:59: note: in instantiation of member function 'boost::spirit::traits::assign_to_attribute_from_value<ident,
      boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, void>::call' requested here
            assign_to_attribute_from_value<Attribute, T>::call(val, attr);
                                                          ^
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/detail/assign_to.hpp:353:9: note: (skipping 7 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
        detail::assign_to(val, attr, is_not_wrapped_container());
        ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/tokenize_and_parse.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/grammar.hpp:18:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/rule.hpp:16:
In file included from /home/wlynch/Boost/1.47.0/include/boost/function.hpp:64:
In file included from /home/wlynch/Boost/1.47.0/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:67:
In file included from /home/wlynch/Boost/1.47.0/include/boost/function/detail/function_iterate.hpp:14:
In file included from /home/wlynch/Boost/1.47.0/include/boost/function/detail/maybe_include.hpp:33:
/home/wlynch/Boost/1.47.0/include/boost/function/function_template.hpp:1042:5: note: in instantiation of function template specialization 'boost::function4<bool,
      boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>,
      lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > &, boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *,
      boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > const &, boost::spirit::context<boost::fusion::cons<ident &,
      boost::fusion::nil>, boost::fusion::vector0<void> > &, boost::spirit::unused_type const
      &>::function4<boost::spirit::qi::detail::parser_binder<boost::spirit::lex::reference<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> const, unsigned long>, mpl_::bool_<1> > >'
      requested here
    base_type(f)
    ^
/home/wlynch/Boost/1.47.0/include/boost/function/function_template.hpp:1083:5: note: in instantiation of function template specialization 'boost::function<bool
      (boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>,
      lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > &, boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *,
      boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > const &, boost::spirit::context<boost::fusion::cons<ident &,
      boost::fusion::nil>, boost::fusion::vector0<void> > &, boost::spirit::unused_type const
      &)>::function<boost::spirit::qi::detail::parser_binder<boost::spirit::lex::reference<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> const, unsigned long>, mpl_::bool_<1> > >'
      requested here
    self_type(f).swap(*this);
    ^
In file included from ../reduced-example/reduced.cpp:3:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/lex/tokenize_and_parse.hpp:15:
In file included from /home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/grammar.hpp:18:
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/rule.hpp:182:19: note: in instantiation of function template specialization 'boost::function<bool
      (boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>,
      lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > &, boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *,
      boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > > const &, boost::spirit::context<boost::fusion::cons<ident &,
      boost::fusion::nil>, boost::fusion::vector0<void> > &, boost::spirit::unused_type const
      &)>::operator=<boost::spirit::qi::detail::parser_binder<boost::spirit::lex::reference<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> const, unsigned long>, mpl_::bool_<1> > >'
      requested here
            lhs.f = detail::bind_parser<Auto>(
                  ^
/home/wlynch/Boost/1.47.0/include/boost/spirit/home/qi/nonterminal/rule.hpp:230:13: note: in instantiation of function template specialization
      'boost::spirit::qi::rule<boost::spirit::lex::lexertl::iterator<boost::spirit::lex::lexertl::functor<boost::spirit::lex::lexertl::token<char const *, boost::mpl::vector0<mpl_::na>, mpl_::bool_<1>, unsigned
      long>, lexertl::detail::data, char const *, mpl_::bool_<1>, mpl_::bool_<1> > >, ident (), boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>::define<mpl_::bool_<1>,
      boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> >' requested here
            define<mpl::true_>(r, expr, traits::matches<qi::domain, Expr>());
            ^
../reduced-example/reduced.cpp:23:9: note: in instantiation of function template specialization 'boost::spirit::qi::operator%=<boost::spirit::lex::token_def<std::basic_string<char>, char, unsigned long> >'
      requested here
                start %= lexer.identifier;
                      ^

推荐答案

我最终意识到我定义的结构体实际上被用作元组.因为 Spirit 会尽量减少组(例如，optional 是 optional).因此，我猜测 tuple 将转换为 A.似乎是这样.

I ended up realizing that the struct I defined is being used in spirit as a tuple. Because spirit will try to minimize the groups (like, an optional<int, int> is an optional<int>). Therefore, I guessed that a tuple<A> will be converted to an A. Which seems to be the case.

我能够将损坏代码的测试用例进一步减少到以下内容:

I was able to further reduce the test case of broken code to the following:

#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/spirit/home/qi.hpp>
#include <string>

struct ident {
    std::string a;
};

BOOST_FUSION_ADAPT_STRUCT(ident,
        (std::string, a)
        )

int main() {
    boost::spirit::qi::rule<const char*, ident()> r;
    r = boost::spirit::lexeme["abc"];
}

来自以下邮件列表帖子(1、2)，我可以通过以下方式解决这个问题:

From the following mailing list postings (1, 2) that I found, I can work around this issue by doing:

r = boost::spirit::lexeme["abc"] >> boost::spirit::eps;

虽然不是很优雅，但至少解决了问题.如果其他人有一种方法来做单元素结构，我会非常感兴趣.

While not really elegant, it solves the problem at least. If someone else has a method to do the single element struct, I'd be greatly interested though.

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