You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and dots ('.'), can be up to 35 characters long. Letters must be lowercase.
270 lines
9.4 KiB
270 lines
9.4 KiB
// 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
|
|
|