I'm trying to build a parser that does a fairly simple transformation of an input string - kind of like an L-System.

I can get rules to properly match the input string, but I'm having real trouble with DOING anything. For testing,

I've created some simple actions and a grammar (and rules) with a closure. When I don't use the closure for

"temporary" variables, I seem to be able to proceed, but when I do anything except assign a value to my closure

result, I'm getting failures to compile. This is using gcc4.01 on MacOSX and spirit 1.8.3 (from boost 1.34).

The specific compiler error is:

../../src/lsystem/catalog_lsystem.cpp: In member function 'void do_appender::act(T&, const IteratorT&, const IteratorT&) const [with T = phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >, IteratorT = __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >]':

<snip>

../../src/lsystem/catalog_lsystem.cpp:211: error: no matching function for call to 'std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >&)'

From the error, it appears that I need some transformation from phoenix::actor

back into my closure member, which is a String (typedef for std::basic_string<char>).

Any suggestions?

do_appender (a simple example actor) looks like:

struct do_appender {

template <typename T, typename ValueT>

void act(T& ref, ValueT const &val) const

{

ref += val;

}

template <typename T, typename IteratorT>

void act(T& ref, IteratorT const &first, IteratorT const & last) const

{

String s(first, last);

ref += s;

}

};

template <typename T>

inline ref_value_actor<T, do_appender>

do_append(T& lhs)

{

return ref_value_actor<T, do_appender>(lhs);

}

template <typename T, typename ValueT>

inline ref_const_ref_actor<T, ValueT, do_appender>

do_append(T& lhs, ValueT const& val)

{

return ref_const_ref_actor<T, ValueT, do_appender>(lhs,val);

}

and the closure and grammar (stripped slightly) look like:

struct ProductionClosure : boost::spirit::closure<ProductionClosure, String, size_t, String>

{

member1 m_result;

member2 m_count;

member3 m_temporary;

};

struct ParameterLSystem::ProductionGrammar

: public grammar<ParameterLSystem::ProductionGrammar, ProductionClosure::context_t>

{

String * m_append;

ProductionGrammar(String * ap) : m_append(ap) {}

template <typename ScannerT>

struct definition {

typedef rule<ScannerT, ProductionClosure::context_t> rule_t;

typedef rule<ScannerT> srule_t;

srule_t r_segment;

rule_t r_segments;

srule_t r_leaf;

rule_t r_leaves;

srule_t r_push;

srule_t r_pop;

rule_t r_start;

rule_t r_terminalLeaves;

rule_t r_branch;

rule_t r_top;

definition(ProductionGrammar const& self)

{

// basics

r_leaf = ch_p('L');

r_leaves = (+r_leaf)[r_leaves.m_result = construct_<String>(arg1, arg2)];

r_segment = ch_p('S');

r_segments = (+r_segment)[r_segments.m_result = construct_<String>(arg1, arg2)];

r_push = ch_p('[');

r_pop = ch_p(']');

r_terminalLeaves = r_push[do_append(r_terminalLeaves.m_result)];

r_top = r_branch[self.m_result = arg1];

}

rule_t const& start() const {

return r_top;

}

};

String is a typedef for std::basic_string<char> in my namespace.

When I use m_append for a "temporary", I can get things to "work", i.e.,

it compiles and generates the correct output but the grammar will get more complex

and I don't believe I can get away without using a closure variable.

The full error stack from the compiler is:

../../../../opensource/opt/include/boost/spirit/actor/ref_value_actor.hpp:59: instantiated from 'void boost::spirit::ref_value_actor<T, ActionT>::operator()(const IteratorT&, const IteratorT&) const [with IteratorT = __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, T = phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >, ActionT = do_appender]'

../../../../opensource/opt/include/boost/spirit/core/scanner/scanner.hpp:146: instantiated from 'static void boost::spirit::attributed_action_policy<boost::spirit::nil_t>::call(const ActorT&, boost::spirit::nil_t, const IteratorT&, const IteratorT&) [with ActorT = boost::spirit::ref_value_actor<phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >, do_appender>, IteratorT = __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >]'

../../../../opensource/opt/include/boost/spirit/core/scanner/scanner.hpp:161: instantiated from 'void boost::spirit::action_policy::do_action(const ActorT&, AttrT&, const IteratorT&, const IteratorT&) const [with ActorT = boost::spirit::ref_value_actor<phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >, do_appender>, AttrT = boost::spirit::nil_t, IteratorT = __gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >]'

../../../../opensource/opt/include/boost/spirit/core/composite/actions.hpp:109: instantiated from 'typename boost::spirit::parser_result<boost::spirit::action<ParserT, ActionT>, ScannerT>::type boost::spirit::action<ParserT, ActionT>::parse(const ScannerT&) const [with ScannerT = boost::spirit::scanner<__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::spirit::scanner_policies<boost::spirit::iter_policy_t, boost::spirit::match_policy, boost::spirit::action_policy> >, ParserT = boost::spirit::rule<boost::spirit::scanner<__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::spirit::scanner_policies<boost::spirit::iter_policy_t, boost::spirit::match_policy, boost::spirit::action_policy> >, boost::spirit::nil_t, boost::spirit::nil_t>, ActionT = boost::spirit::ref_value_actor<phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >, do_appender>]'

../../../../opensource/opt/include/boost/spirit/core/non_terminal/impl/rule.ipp:233: instantiated from 'typename boost::spirit::match_result<ScannerT, ContextResultT>::type boost::spirit::impl::concrete_parser<ParserT, ScannerT, AttrT>::do_parse_virtual(const ScannerT&) const [with ParserT = boost::spirit::action<boost::spirit::rule<boost::spirit::scanner<__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::spirit::scanner_policies<boost::spirit::iter_policy_t, boost::spirit::match_policy, boost::spirit::action_policy> >, boost::spirit::nil_t, boost::spirit::nil_t>, boost::spirit::ref_value_actor<phoenix::actor<phoenix::closure_member<0, phoenix::closure<String, size_t, String> > >, do_appender> >, ScannerT = boost::spirit::scanner<__gnu_cxx::__normal_iterator<char*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::spirit::scanner_policies<boost::spirit::iter_policy_t, boost::spirit::match_policy, boost::spirit::action_policy> >, AttrT = String]'

../../src/lsystem/catalog_lsystem.cpp:547: instantiated from here