#ifndef SPROUT_WEED_PARSER_DIRECTIVE_OMIT_HPP #define SPROUT_WEED_PARSER_DIRECTIVE_OMIT_HPP #include <cstddef> #include <sprout/config.hpp> #include <sprout/type_traits/identity.hpp> #include <sprout/weed/unused.hpp> #include <sprout/weed/parser_result.hpp> #include <sprout/weed/expr/make_terminal_or_expr.hpp> #include <sprout/weed/expr/eval.hpp> #include <sprout/weed/parser/parser_base.hpp> #include <sprout/weed/traits/expr/terminal_or_expr_of.hpp> #include <sprout/weed/traits/parser/attribute_of.hpp> namespace sprout { namespace weed { // // omit_p // template<typename Parser> struct omit_p : public sprout::weed::parser_base { public: template<typename Context, typename Iterator> struct attribute : public sprout::identity<sprout::weed::unused> {}; template<typename Context, typename Iterator> struct result : public sprout::identity<sprout::weed::parser_result<Iterator, typename attribute<Context, Iterator>::type> > {}; private: typedef typename sprout::weed::traits::terminal_or_expr_of<Parser>::type expr_type; private: expr_type expr_; private: template<typename Context, typename Iterator, typename Result> SPROUT_CONSTEXPR typename result<Context, Iterator>::type call( Iterator first, Result const& res ) const { typedef typename result<Context, Iterator>::type result_type; typedef typename attribute<Context, Iterator>::type attribute_type; return res.success() ? result_type(true, res.current(), attribute_type()) : result_type(false, first, attribute_type()) ; } public: omit_p() = default; explicit SPROUT_CONSTEXPR omit_p( Parser const& p ) : expr_(sprout::weed::make_terminal_or_expr(p)) {} template<typename Context, typename Iterator> SPROUT_CONSTEXPR typename result<Context, Iterator>::type operator()( Iterator first, Iterator last, Context const& ctx ) const { return call<Context>(first, sprout::weed::eval(expr_, ctx)); } }; // // omit_d // struct omit_d { public: template<typename Parser> SPROUT_CONSTEXPR sprout::weed::omit_p<Parser> operator[](Parser const& p) const { return sprout::weed::omit_p<Parser>(p); } }; // // omit // SPROUT_CONSTEXPR sprout::weed::omit_d omit = sprout::weed::omit_d(); } // namespace weed } // namespace sprout #endif // #ifndef SPROUT_WEED_PARSER_DIRECTIVE_OMIT_HPP