[Boost-users] spirit help: segfault

Subject: [Boost-users] spirit help: segfault
From: Littlefield, Tyler (tyler_at_[hidden])
Date: 2015-09-24 20:26:00

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Hello all:
I'm getting a segfault when I run this. It looks like the debug
prints, but when I debug it I just get an endless loop of backtrace.
If anyone can help point me in the right direction, I'd appreciate it.
I'd also appreciate, if possible any tips/tricks for cleaning up this
grammar.

Thanks!

//code here:
/***
*I-EBNF parser
*
*This defines a grammar for BNF.
*/

//Speeds up compilation times.
//This is a relatively small grammar, this is useful.
#define BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
#define BOOST_SPIRIT_QI_DEBUG

#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
#include <boost/fusion/adapted.hpp>
#include <boost/fusion/support.hpp>
#include <vector>
#include <string>
#include <iostream>

namespace Parser
{

namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;

enum class RHSType
{
    Terminal, Identifier
};
struct RHS
{
    RHSType type;
    std::string value;
};
struct Rule
{
    std::string identifier; //lhs
    std::vector<RHS> rhs;
};
}

//expose our structs to fusion:
BOOST_FUSION_ADAPT_STRUCT(
    Parser::RHS,
    (Parser::RHSType, type)
    (std::string, value)
)
BOOST_FUSION_ADAPT_STRUCT(
    Parser::Rule,
    (std::string, identifier)
    (std::vector<Parser::RHS>, rhs)
)

namespace Parser
{
typedef std::vector<Rule> RuleList;

//our grammar definition
template <typename Iterator>
struct Grammar: qi::grammar<Iterator, std::list<Rule>, ascii::space_type>
{
    Grammar(): Grammar::base_type(rules)
    {
        qi::char_type char_;

        letter = char_("a-zA-Z");
        digit = char_('0', '9');
        symbol = char_('[') | ']' | '[' | ']' | '(' | ')' | '<' | '>'
| '\'' | '\"' | '=' | '|' | '.' | ',' | ';';
        character = letter | digit | symbol | '_';
        identifier = letter >> *(letter | digit | '_');
        terminal = (char_('\'') >> character >> *character >>
char_('\'')) | (char_('\"') >> character >> *character >> char_('\"'));
        lhs = identifier;
        rhs = terminal | identifier | char_('[') >> rhs >> char_(']')
| char_('{') >> rhs >> char_('}') | char_('(') >> rhs >> char_(')') |
rhs >> char_('|') >> rhs | rhs >> char_(',') >> rhs;
        rule = identifier >> char_('=') >> rhs;
        rules = rule >> *rule;
    }

private:
    qi::rule<Iterator, char(), ascii::space_type> letter, digit,
symbol, character;
    qi::rule<Iterator, std::string(), ascii::space_type> identifier,
lhs, terminal;
    qi::rule<Iterator, RHS, ascii::space_type> rhs;
    qi::rule<Iterator, Rule, ascii::space_type> rule;
    qi::rule<Iterator, std::list<Rule>, ascii::space_type> rules;
};

}

int main()
{
    Parser::Grammar<std::string::const_iterator> parser;
    boost::spirit::ascii::space_type space;
    std::string input;
    std::vector<std::string> output;
    bool result;

    while (std::getline(std::cin, input))
        {
            if (input.empty())
                {
                    break;
                }
            std::string::const_iterator it, itEnd;
            it = input.begin();
            itEnd = input.end();
            result = phrase_parse(it, itEnd, parser, space, output);
            if (result && it == itEnd)
                {
                    std::cout << "success" << std::endl;
                }
        }

    return 0;
}

- -- 
Take care,
Ty
twitter: @sorressean
web:http://tysdomain.com
pubkey: http://tysdomain.com/files/pubkey.asc
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