Boost Users :
Subject: Re: [Boost-users] [Spirit/Qi/Phoenix] non compiling rules...
From: TONGARI J (tongari95_at_[hidden])
Date: 2013-12-12 09:24:33
2013/12/12 Francois Mauger <mauger_at_[hidden]>
> Dear Boosters,
> The following code is one of my first attempts to use Spirit/Qi.
> For my education, I have tried 2 techniques to parse the simple "aaa=131;"
> The first one (Block A) compiles and seems to output the expected result.
> The second (B) does not compile with a huge massively templatized
> backtrace that I don't understand.
> What is the difference between using online rules and
> rule objects ? Is there a syntax error somewhere ?
> I'm afraid the documentation and example are rather terse about the
> syntax to be used here when coupling Qi and Phoenix...
> boost::spirit::qi::rule<std::string::iterator> key_rule = +(char_ -
> boost::spirit::qi::rule<std::string::iterator> value_rule =
> lexeme[+(char_ - ';')];
> bool r = phrase_parse(
> key_rule[boost::phoenix::ref(vkey) =
> boost::spirit::qi::_1 ] // <----HERE
> >> '=' >> *space
> >> value_rule[boost::phoenix::ref(vvalue) =
> boost::spirit::qi::_1 ], // <----HERE
The problem is (at least what I see): your key_rule/value_rule have no
attribute, so qi::_1 eventually evaluates to nothing (i.e. unused_type).
To give them attr, for example:
And I'd suggest using attr propagation instead of the explicit semantic
action if possible.
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