// 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 | |
{ | |
using spirit::set_state; | |
using spirit::in_state; | |
/////////////////////////////////////////////////////////////////////////// | |
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(detail::set_lexer_state(it_, traits::get_c_string(state_))) | |
{} | |
~reset_state_on_exit() | |
{ | |
// reset the state of the underlying lexer instance | |
detail::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 |