I am trying to use the no_skip
directive to parse input of the form:
state PASS
<tab> state FAIL
I am using ascii::blank
as my skipper. I get an compile error when I wrap no_skip[ trans_assign_expr ]
to parse for the tab.
How do I fix this error, and in general, how do I understand these errors so that I can fix future ones? The boost spirit documentation never covers this aspect of using spirit :(
This is the error
In file included from /usr/include/boost/spirit/home/qi/nonterminal/grammar.hpp:18:0, from /usr/include/boost/spirit/include/qi_grammar.hpp:16, from ../src/RJstate.cpp:9: /usr/include/boost/spirit/home/qi/nonterminal/rule.hpp: In member function ‘bool boost::spirit::qi::rule::parse(Iterator&, const Iterator&, Context&, const Skipper&, Attribute&) const [with Context = boost::spirit::context, boost::fusion::vector0 >, Skipper = boost::spirit::qi::detail::unused_skipper > >, Attribute = const boost::spirit::unused_type, Iterator = __gnu_cxx::__normal_iterator >, T1 = boost::proto::exprns_::expr >, 0l>, T2 = boost::spirit::unused_type, T3 = boost::spirit::unused_type, T4 = boost::spirit::unused_type]’: /usr/include/boost/spirit/home/qi/reference.hpp:43:71: instantiated from ‘bool boost::spirit::qi::reference::parse(Iterator&, const Iterator&, Context&, const Skipper&, Attribute&) const [with Iterator = __gnu_cxx::__normal_iterator >, Context = boost::spirit::context, boost::fusion::vector0 >, Skipper = boost::spirit::qi::detail::unused_skipper > >, Attribute = const boost::spirit::unused_type, Subject = const boost::spirit::qi::rule >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>]’ /usr/include/boost/spirit/home/qi/directive/no_skip.hpp:64:63: instantiated from ‘bool boost::spirit::qi::no_skip_directive::parse(Iterator&, const Iterator&, Context&, const Skipper&, Attribute&) const [with Iterator = __gnu_cxx::__normal_iterator >, Context = boost::spirit::context, boost::fusion::vector0 >, Skipper = boost::spirit::qi::char_class >, Attribute = const boost::spirit::unused_type, Subject = boost::spirit::qi::reference >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> >]’ /usr/include/boost/spirit/home/qi/detail/fail_function.hpp:45:74: instantiated from ‘bool boost::spirit::qi::detail::fail_function::operator()(const Component&) const [with Component = boost::spirit::qi::no_skip_directive >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> > >, Iterator = __gnu_cxx::__normal_iterator >, Context = boost::spirit::context, boost::fusion::vector0 >, Skipper = boost::spirit::qi::char_class >]’ /usr/include/boost/fusion/algorithm/query/detail/any.hpp:42:83: [ skipping 8 instantiation contexts ] /usr/include/boost/function/function_template.hpp:132:42: instantiated from ‘static R boost::detail::function::function_obj_invoker4::invoke(boost::detail::function::function_buffer&, T0, T1, T2, T3) [with FunctionObj = boost::spirit::qi::detail::parser_binder >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> >, boost::fusion::cons >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> > >, boost::fusion::nil> > > >, mpl_::bool_ >, R = bool, T0 = __gnu_cxx::__normal_iterator >&, T1 = const __gnu_cxx::__normal_iterator >&, T2 = boost::spirit::context, boost::fusion::vector0 >&, T3 = const boost::spirit::qi::char_class >&]’ /usr/include/boost/function/function_template.hpp:913:60: instantiated from ‘void boost::function4::assign_to(Functor) [with Functor = boost::spirit::qi::detail::parser_binder >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> >, boost::fusion::cons >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> > >, boost::fusion::nil> > > >, mpl_::bool_ >, R = bool, T0 = __gnu_cxx::__normal_iterator >&, T1 = const __gnu_cxx::__normal_iterator >&, T2 = boost::spirit::context, boost::fusion::vector0 >&, T3 = const boost::spirit::qi::char_class >&]’ /usr/include/boost/function/function_template.hpp:722:7: instantiated from ‘boost::function4::function4(Functor, typename boost::enable_if_c::value>::value, int>::type) [with Functor = boost::spirit::qi::detail::parser_binder >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> >, boost::fusion::cons >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> > >, boost::fusion::nil> > > >, mpl_::bool_ >, R = bool, T0 = __gnu_cxx::__normal_iterator >&, T1 = const __gnu_cxx::__normal_iterator >&, T2 = boost::spirit::context, boost::fusion::vector0 >&, T3 = const boost::spirit::qi::char_class >&, typename boost::enable_if_c::value>::value, int>::type = int]’ /usr/include/boost/function/function_template.hpp:1064:16: instantiated from ‘boost::function::function(Functor, typename boost::enable_if_c::value>::value, int>::type) [with Functor = boost::spirit::qi::detail::parser_binder >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> >, boost::fusion::cons >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> > >, boost::fusion::nil> > > >, mpl_::bool_ >, R = bool, T0 = __gnu_cxx::__normal_iterator >&, T1 = const __gnu_cxx::__normal_iterator >&, T2 = boost::spirit::context, boost::fusion::vector0 >&, T3 = const boost::spirit::qi::char_class >&, typename boost::enable_if_c::value>::value, int>::type = int]’ /usr/include/boost/function/function_template.hpp:1105:5: instantiated from ‘typename boost::enable_if_c::value>::value, boost::function&>::type boost::function::operator=(Functor) [with Functor = boost::spirit::qi::detail::parser_binder >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> >, boost::fusion::cons >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type> > >, boost::fusion::nil> > > >, mpl_::bool_ >, R = bool, T0 = __gnu_cxx::__normal_iterator >&, T1 = const __gnu_cxx::__normal_iterator >&, T2 = boost::spirit::context, boost::fusion::vector0 >&, T3 = const boost::spirit::qi::char_class >&, typename boost::enable_if_c::value>::value, boost::function&>::type = boost::function >&, const __gnu_cxx::__normal_iterator >&, boost::spirit::context, boost::fusion::vector0 >&, const boost::spirit::qi::char_class >&)>&]’ /usr/include/boost/spirit/home/qi/nonterminal/rule.hpp:198:13: instantiated from ‘boost::spirit::qi::rule& boost::spirit::qi::rule::operator=(const Expr&) [with Expr = boost::proto::exprns_::expr >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>&, const boost::proto::exprns_::expr, 0l>&>, 2l>&, const boost::proto::exprns_::expr, 0l>&, boost::spirit::qi::rule >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>&>, 2l>&>, 2l>, Iterator = __gnu_cxx::__normal_iterator >, T1 = boost::proto::exprns_::expr >, 0l>, T2 = boost::spirit::unused_type, T3 = boost::spirit::unused_type, T4 = boost::spirit::unused_type, boost::spirit::qi::rule = boost::spirit::qi::rule >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>]’ ../src/RJstate.cpp:49:7: instantiated from ‘fsm_grammar::fsm_grammar() [with Iterator = __gnu_cxx::__normal_iterator >, Skipper = boost::proto::exprns_::expr >, 0l>]’ ../src/RJstate.cpp:112:50: instantiated from here /usr/include/boost/spirit/home/qi/nonterminal/rule.hpp:277:17: error: no match for call to ‘(const function_type {aka const boost::function >&, const __gnu_cxx::__normal_iterator >&, boost::spirit::context, boost::fusion::vector0 >&, const boost::spirit::qi::char_class >&)>}) (__gnu_cxx::__normal_iterator >&, const __gnu_cxx::__normal_iterator >&, boost::spirit::qi::rule >, boost::proto::exprns_::expr >, 0l>, boost::spirit::unused_type, boost::spirit::unused_type, boost::spirit::unused_type>::context_type&, const boost::spirit::qi::detail::unused_skipper > >&)’ /usr/include/boost/function/function_template.hpp:1043:7: note: candidate is: /usr/include/boost/function/function_template.hpp:1006:1: note: boost::function4::result_type boost::function4::operator()(T0, T1, T2, T3) const [with R = bool, T0 = __gnu_cxx::__normal_iterator >&, T1 = const __gnu_cxx::__normal_iterator >&, T2 = boost::spirit::context, boost::fusion::vector0 >&, T3 = const boost::spirit::qi::char_class >&, boost::function4::result_type = bool] /usr/include/boost/function/function_template.hpp:1006:1: note: no known conversion for argument 4 from ‘const boost::spirit::qi::detail::unused_skipper > >’ to ‘const boost::spirit::qi::char_class >&’
This is my code
#define BOOST_SPIRIT_DEBUG
#include <iostream>
#include <vector>
#include <iterator>
#include <fstream>
// forwards to <boost/spirit/home/qi/nonterminal/grammar.hpp>
#include <boost/spirit/include/qi_grammar.hpp>
// forwards to <boost/spirit/home/qi/nonterminal/rule.hpp>
#include <boost/spirit/include/qi_rule.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/qi_char_class.hpp>
#include <boost/spirit/include/qi_no_skip.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include "TestParser.hpp"
///////////////////////////////////////////////////////////////////////////////
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
template <typename Iterator, typename Skipper=qi::space_type>
struct fsm_grammar : qi::grammar<Iterator, Skipper>
{
fsm_grammar() : fsm_grammar::base_type(script)
{
using boost::spirit::double_;
using boost::spirit::ascii::char_;
using boost::spirit::ascii::alnum;
using boost::spirit::ascii::alpha;
using boost::spirit::lit;
using boost::spirit::qi::eol;
using boost::spirit::qi::eoi;
using boost::spirit::lexeme;
using boost::spirit::qi::no_skip;
using boost::spirit::qi::_1;
using boost::spirit::qi::_val;
//id = char_("a-zA-Z")[_val += _1] >> *char_("a-zA-Z_0-9")[_val += _1];
id = lexeme[ alpha[_val += _1] >> *alnum[_val += _1] >> !alnum ];
state_id = "state" >> id;
start_expr = "start" >> id;
trans_assign_expr = lit("\t") >> state_id >> +(char_('a','z'));
trans_expr = state_id >> eol >> no_skip[ trans_assign_expr ];
assign_expr = char_("a-zA-Z");
states_list = "states" >> +(id);
expr = (trans_expr | start_expr | states_list) >> +eol;
script = *expr >> eoi;
BOOST_SPIRIT_DEBUG_NODE(script);
BOOST_SPIRIT_DEBUG_NODE(states_list);
BOOST_SPIRIT_DEBUG_NODE(expr);
BOOST_SPIRIT_DEBUG_NODE(start_expr);
BOOST_SPIRIT_DEBUG_NODE(assign_expr);
BOOST_SPIRIT_DEBUG_NODE(trans_expr);
BOOST_SPIRIT_DEBUG_NODE(trans_assign_expr);
BOOST_SPIRIT_DEBUG_NODE(state_id);
BOOST_SPIRIT_DEBUG_NODE(id);
std::string val = "PASS";
//test_parser(" ",+char_("a-zA-Z"));
}
qi::rule<Iterator, Skipper> script;
qi::rule<Iterator, Skipper> states_list;
qi::rule<Iterator, Skipper> expr;
qi::rule<Iterator, Skipper> trans_expr;
qi::rule<Iterator, Skipper> trans_assign_expr;
qi::rule<Iterator, Skipper> assign_expr;
qi::rule<Iterator, Skipper> start_expr;
qi::rule<Iterator, Skipper> state_id;
qi::rule<Iterator, std::string()> id;
};
As llonesmiz very aptly pointed out:
****** like this in the error 'novel' ******
)look for comments directly (I mean, directly) above a 'failing' line. This includes the points at which template instantiations were triggered.
If you are seeing a compilation error here stating that the forth parameter can't be converted to a required target type then you are probably trying to use a rule or a grammar with an incompatible skipper type.
In this case, since you want to use trans_assign_expr
without a skipper, you must declare it without one:
// no skippers
qi::rule<Iterator, std::string()> id;
qi::rule<Iterator> state_id;
qi::rule<Iterator> trans_assign_expr;
This makes it compile. The output suggests it doesn't /work/, though.
I'm not convinced this is what you want to do. Since lexeme
seems to be a better option here, anyway. I'd simplify the id
rule:
id = lexeme [ alpha >> *alnum ];
lexeme
already has the property of locally disabling the Skipper in use.
Here is a slight change of the grammar http://liveworkspace.org/code/70f3319342c567854b9f785ac13508d6
trans_assign_expr = state_id >> +(char_('a','z'));
trans_expr = state_id >> no_skip [ eol >> '\t' ] >> trans_assign_expr;
As you can see, I include the with eol
in a no_skip (to avoid the skipper eating the tab). This way, the skipper is still in effect in trans_assign_expr
- which makes it accept the extra space. Given the input
const char input[]="state PASS\n\t state FAIL more";
The output is now
<script>
<try>state PASS\n\t state F</try>
<expr>
<try>state PASS\n\t state F</try>
<trans_expr>
<try>state PASS\n\t state F</try>
<state_id>
<try>state PASS\n\t state F</try>
<id>
<try> PASS\n\t state FAIL m</try>
<success>\n\t state FAIL more\n</success>
<attributes>[[P, A, S, S]]</attributes>
</id>
<success>\n\t state FAIL more\n</success>
<attributes>[]</attributes>
</state_id>
<trans_assign_expr>
<try> state FAIL more\n</try>
<state_id>
<try> state FAIL more\n</try>
<id>
<try> FAIL more\n</try>
<success> more\n</success>
<attributes>[[F, A, I, L]]</attributes>
</id>
<success> more\n</success>
<attributes>[]</attributes>
</state_id>
<success>\n</success>
<attributes>[]</attributes>
</trans_assign_expr>
<success>\n</success>
<attributes>[]</attributes>
</trans_expr>
<success></success>
<attributes>[]</attributes>
</expr>
<expr>
<try></try>
<trans_expr>
<try></try>
<state_id>
<try></try>
<fail/>
</state_id>
<fail/>
</trans_expr>
<start_expr>
<try></try>
<fail/>
</start_expr>
<states_list>
<try></try>
<fail/>
</states_list>
<fail/>
</expr>
<success></success>
<attributes>[]</attributes>
</script>
true
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