comparison DEPENDENCIES/generic/include/boost/spirit/home/lex/qi/state_switcher.hpp @ 16:2665513ce2d3

Add boost headers

+//  Copyright (c) 2001-2011 Hartmut Kaiser
+//  Copyright (c)      2010 Bryce Lelbach
+//
+//  Distributed under the Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#if !defined(BOOST_SPIRIT_LEX_STATE_SWITCHER_SEP_23_2007_0714PM)
+#define BOOST_SPIRIT_LEX_STATE_SWITCHER_SEP_23_2007_0714PM
+
+#if defined(_MSC_VER)
+#pragma once
+#endif
+
+#include <boost/spirit/home/support/info.hpp>
+#include <boost/spirit/home/qi/detail/attributes.hpp>
+#include <boost/spirit/home/support/common_terminals.hpp>
+#include <boost/spirit/home/support/string_traits.hpp>
+#include <boost/spirit/home/support/has_semantic_action.hpp>
+#include <boost/spirit/home/support/handles_container.hpp>
+#include <boost/spirit/home/qi/skip_over.hpp>
+#include <boost/spirit/home/qi/domain.hpp>
+#include <boost/spirit/home/qi/parser.hpp>
+#include <boost/spirit/home/qi/meta_compiler.hpp>
+#include <boost/mpl/print.hpp>
+
+namespace boost { namespace spirit
+{
+    ///////////////////////////////////////////////////////////////////////////
+    // Enablers
+    ///////////////////////////////////////////////////////////////////////////
+
+    // enables set_state(s)
+    template <typename A0>
+    struct use_terminal<qi::domain
+      , terminal_ex<tag::set_state, fusion::vector1<A0> >
+    > : traits::is_string<A0> {};
+
+    // enables *lazy* set_state(s)
+    template <>
+    struct use_lazy_terminal<
+        qi::domain, tag::set_state, 1
+    > : mpl::true_ {};
+
+    // enables in_state(s)[p]
+    template <typename A0>
+    struct use_directive<qi::domain
+      , terminal_ex<tag::in_state, fusion::vector1<A0> >
+    > : traits::is_string<A0> {};
+
+    // enables *lazy* in_state(s)[p]
+    template <>
+    struct use_lazy_directive<
+        qi::domain, tag::in_state, 1
+    > : mpl::true_ {};
+
+}}
+
+namespace boost { namespace spirit { namespace qi
+{
+#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
+    using spirit::set_state;
+    using spirit::in_state;
+#endif
+    using spirit::set_state_type;
+    using spirit::in_state_type;
+
+    ///////////////////////////////////////////////////////////////////////////
+    namespace detail
+    {
+        template <typename Iterator>
+        inline std::size_t
+        set_lexer_state(Iterator& it, std::size_t state)
+        {
+            return it.set_state(state);
+        }
+
+        template <typename Iterator, typename Char>
+        inline std::size_t
+        set_lexer_state(Iterator& it, Char const* statename)
+        {
+            std::size_t state = it.map_state(statename);
+
+            //  If the following assertion fires you probably used the
+            //  set_state(...) or in_state(...)[...] lexer state switcher with
+            //  a lexer state name unknown to the lexer (no token definitions
+            //  have been associated with this lexer state).
+            BOOST_ASSERT(std::size_t(~0) != state);
+            return it.set_state(state);
+        }
+    }
+
+    ///////////////////////////////////////////////////////////////////////////
+    //  Parser switching the state of the underlying lexer component.
+    //  This parser gets used for the set_state(...) construct.
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename State>
+    struct state_switcher
+      : primitive_parser<state_switcher<State> >
+    {
+        typedef typename 
+            remove_const<typename traits::char_type_of<State>::type>::type 
+        char_type;
+        typedef std::basic_string<char_type> string_type;
+
+        template <typename Context, typename Iterator>
+        struct attribute
+        {
+            typedef unused_type type;
+        };
+
+        state_switcher(char_type const* state)
+          : state(state) {}
+
+        template <typename Iterator, typename Context
+          , typename Skipper, typename Attribute>
+        bool parse(Iterator& first, Iterator const& last
+          , Context& /*context*/, Skipper const& skipper
+          , Attribute& /*attr*/) const
+        {
+            qi::skip_over(first, last, skipper);   // always do a pre-skip
+
+            // just switch the state and return success
+            detail::set_lexer_state(first, state.c_str());
+            return true;
+        }
+
+        template <typename Context>
+        info what(Context& /*context*/) const
+        {
+            return info("set_state");
+        }
+
+        string_type state;
+    };
+
+    ///////////////////////////////////////////////////////////////////////////
+    namespace detail
+    {
+        template <typename Iterator>
+        struct reset_state_on_exit
+        {
+            template <typename State>
+            reset_state_on_exit(Iterator& it_, State state_)
+              : it(it_)
+              , state(set_lexer_state(it_, traits::get_c_string(state_))) 
+            {}
+
+            ~reset_state_on_exit()
+            {
+                // reset the state of the underlying lexer instance
+                set_lexer_state(it, state);
+            }
+
+            Iterator& it;
+            std::size_t state;
+
+        private:
+            // silence MSVC warning C4512: assignment operator could not be generated
+            reset_state_on_exit& operator= (reset_state_on_exit const&);
+        };
+    }
+
+    ///////////////////////////////////////////////////////////////////////////
+    // Parser, which switches the state of the underlying lexer component
+    // for the execution of the embedded sub-parser, switching the state back
+    // afterwards. This parser gets used for the in_state(...)[p] construct.
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Subject, typename State>
+    struct state_switcher_context 
+      : unary_parser<state_switcher_context<Subject, State> >
+    {
+        typedef Subject subject_type;
+        typedef typename traits::char_type_of<State>::type char_type;
+        typedef typename remove_const<char_type>::type non_const_char_type;
+
+        template <typename Context, typename Iterator>
+        struct attribute
+        {
+            typedef typename
+                traits::attribute_of<subject_type, Context, Iterator>::type
+            type;
+        };
+
+        state_switcher_context(Subject const& subject
+              , typename add_reference<State>::type state)
+          : subject(subject), state(state) {}
+
+        // The following conversion constructors are needed to make the 
+        // in_state_switcher template usable
+        template <typename String>
+        state_switcher_context(
+                state_switcher_context<Subject, String> const& rhs)
+          : subject(rhs.subject), state(traits::get_c_string(rhs.state)) {}
+
+        template <typename Iterator, typename Context
+          , typename Skipper, typename Attribute>
+        bool parse(Iterator& first, Iterator const& last
+          , Context& context, Skipper const& skipper
+          , Attribute& attr) const
+        {
+            qi::skip_over(first, last, skipper);   // always do a pre-skip
+
+            // the state has to be reset at exit in any case
+            detail::reset_state_on_exit<Iterator> guard(first, state);
+            return subject.parse(first, last, context, skipper, attr);
+        }
+
+        template <typename Context>
+        info what(Context& context) const
+        {
+            return info("in_state", subject.what(context));
+        }
+
+        Subject subject;
+        State state;
+
+    private:
+        // silence MSVC warning C4512: assignment operator could not be generated
+        state_switcher_context& operator= (state_switcher_context const&);
+    };
+
+    ///////////////////////////////////////////////////////////////////////////
+    // Parser generators: make_xxx function (objects)
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Modifiers, typename State>
+    struct make_primitive<terminal_ex<tag::set_state, fusion::vector1<State> >
+      , Modifiers, typename enable_if<traits::is_string<State> >::type>
+    {
+        typedef typename add_const<State>::type const_string;
+        typedef state_switcher<const_string> result_type;
+
+        template <typename Terminal>
+        result_type operator()(Terminal const& term, unused_type) const
+        {
+            return result_type(traits::get_c_string(fusion::at_c<0>(term.args)));
+        }
+    };
+
+    template <typename State, typename Subject, typename Modifiers>
+    struct make_directive<terminal_ex<tag::in_state, fusion::vector1<State> >
+      , Subject, Modifiers>
+    {
+        typedef typename add_const<State>::type const_string;
+        typedef state_switcher_context<Subject, const_string> result_type;
+
+        template <typename Terminal>
+        result_type operator()(Terminal const& term, Subject const& subject
+          , unused_type) const
+        {
+            return result_type(subject, fusion::at_c<0>(term.args));
+        }
+    };
+}}}
+
+namespace boost { namespace spirit { namespace traits
+{
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Subject, typename State>
+    struct has_semantic_action<qi::state_switcher_context<Subject, State> >
+      : unary_has_semantic_action<Subject> {};
+
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename Subject, typename State, typename Attribute
+        , typename Context, typename Iterator>
+    struct handles_container<qi::state_switcher_context<Subject, State>
+          , Attribute, Context, Iterator>
+      : unary_handles_container<Subject, Attribute, Context, Iterator> {}; 
+}}}
+
+#endif