| // Copyright (c) 2001-2011 Hartmut Kaiser | |
| // Copyright (c) 2001-2011 Joel de Guzman | |
| // 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_ARGUMENT_JUNE_07_2009_1106AM) | |
| #define BOOST_SPIRIT_LEX_ARGUMENT_JUNE_07_2009_1106AM | |
| #if defined(_MSC_VER) | |
| #pragma once | |
| #endif | |
| #include <boost/spirit/home/phoenix/core/actor.hpp> | |
| #include <boost/spirit/home/phoenix/core/argument.hpp> | |
| #include <boost/spirit/home/phoenix/core/compose.hpp> | |
| #include <boost/spirit/home/phoenix/core/value.hpp> | |
| #include <boost/spirit/home/phoenix/core/as_actor.hpp> | |
| #include <boost/spirit/home/phoenix/operator/self.hpp> | |
| #include <boost/spirit/home/support/string_traits.hpp> | |
| #include <boost/fusion/include/at.hpp> | |
| #include <boost/mpl/at.hpp> | |
| #include <boost/mpl/bool.hpp> | |
| #include <boost/type_traits/is_same.hpp> | |
| #include <boost/type_traits/remove_const.hpp> | |
| /////////////////////////////////////////////////////////////////////////////// | |
| namespace boost { namespace spirit { namespace lex | |
| { | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The state_getter is a Phoenix actor used to access the name of the | |
| // current lexer state by calling get_state_name() on the context (which | |
| // is the 4th parameter to any lexer semantic actions). | |
| // | |
| // This Phoenix actor is invoked whenever the placeholder '_state' is used | |
| // as a rvalue inside a lexer semantic action: | |
| // | |
| // lex::token_def<> identifier = "[a-zA-Z_][a-zA-Z0-9_]*"; | |
| // this->self = identifier [ std::cout << _state ]; | |
| // | |
| // The example shows how to print the lexer state after matching a token | |
| // 'identifier'. | |
| struct state_getter | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef typename | |
| remove_const< | |
| typename mpl::at_c<typename Env::args_type, 4>::type | |
| >::type | |
| context_type; | |
| typedef typename context_type::state_name_type type; | |
| }; | |
| template <typename Env> | |
| typename result<Env>::type | |
| eval(Env const& env) const | |
| { | |
| return fusion::at_c<4>(env.args()).get_state_name(); | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The state_setter is a Phoenix actor used to change the name of the | |
| // current lexer state by calling set_state_name() on the context (which | |
| // is the 4th parameter to any lexer semantic actions). | |
| // | |
| // This Phoenix actor is invoked whenever the placeholder '_state' is used | |
| // as a lvalue inside a lexer semantic action: | |
| // | |
| // lex::token_def<> identifier = "[a-zA-Z_][a-zA-Z0-9_]*"; | |
| // this->self = identifier [ _state = "SOME_LEXER_STATE" ]; | |
| // | |
| // The example shows how to change the lexer state after matching a token | |
| // 'identifier'. | |
| template <typename Actor> | |
| struct state_setter | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef void type; | |
| }; | |
| template <typename Env> | |
| void eval(Env const& env) const | |
| { | |
| typedef typename | |
| remove_const< | |
| typename mpl::at_c<typename Env::args_type, 4>::type | |
| >::type | |
| context_type; | |
| typedef typename context_type::state_name_type string; | |
| fusion::at_c<4>(env.args()).set_state_name( | |
| traits::get_c_string(actor_.eval(env))); | |
| } | |
| state_setter(Actor const& actor) | |
| : actor_(actor) {} | |
| // see explanation for this constructor at the end of this file | |
| state_setter(phoenix::actor<state_getter>, Actor const& actor) | |
| : actor_(actor) {} | |
| Actor actor_; | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The state_context is used as a noop Phoenix actor to create the | |
| // placeholder '_state' (see below). It is a noop actor because it is used | |
| // as a placeholder only, while it is being converted either to a | |
| // state_getter (if used as a rvalue) or to a state_setter (if used as a | |
| // lvalue). The conversion is achieved by specializing and overloading a | |
| // couple of the Phoenix templates from the Phoenix expression composition | |
| // engine (see the end of this file). | |
| struct state_context | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef unused_type type; | |
| }; | |
| template <typename Env> | |
| unused_type | |
| eval(Env const& env) const | |
| { | |
| return unused; | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The value_getter is used to create the _val placeholder, which is a | |
| // Phoenix actor used to access the value of the current token. | |
| // | |
| // This Phoenix actor is invoked whenever the placeholder '_val' is used | |
| // as a rvalue inside a lexer semantic action: | |
| // | |
| // lex::token_def<> identifier = "[a-zA-Z_][a-zA-Z0-9_]*"; | |
| // this->self = identifier [ std::cout << _val ]; | |
| // | |
| // The example shows how to use _val to print the identifier name (which | |
| // is the initial token value). | |
| struct value_getter | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef typename | |
| remove_const< | |
| typename mpl::at_c<typename Env::args_type, 4>::type | |
| >::type | |
| context_type; | |
| typedef typename context_type::get_value_type type; | |
| }; | |
| template <typename Env> | |
| typename result<Env>::type | |
| eval(Env const& env) const | |
| { | |
| return fusion::at_c<4>(env.args()).get_value(); | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The value_setter is a Phoenix actor used to change the name of the | |
| // current lexer state by calling set_state_name() on the context (which | |
| // is the 4th parameter to any lexer semantic actions). | |
| // | |
| // This Phoenix actor is invoked whenever the placeholder '_val' is used | |
| // as a lvalue inside a lexer semantic action: | |
| // | |
| // lex::token_def<> identifier = "[a-zA-Z_][a-zA-Z0-9_]*"; | |
| // this->self = identifier [ _val = "identifier" ]; | |
| // | |
| // The example shows how to change the token value after matching a token | |
| // 'identifier'. | |
| template <typename Actor> | |
| struct value_setter | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef void type; | |
| }; | |
| template <typename Env> | |
| void eval(Env const& env) const | |
| { | |
| fusion::at_c<4>(env.args()).set_value(actor_.eval(env)); | |
| } | |
| value_setter(Actor const& actor) | |
| : actor_(actor) {} | |
| // see explanation for this constructor at the end of this file | |
| value_setter(phoenix::actor<value_getter>, Actor const& actor) | |
| : actor_(actor) {} | |
| Actor actor_; | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The value_context is used as a noop Phoenix actor to create the | |
| // placeholder '_val' (see below). It is a noop actor because it is used | |
| // as a placeholder only, while it is being converted either to a | |
| // value_getter (if used as a rvalue) or to a value_setter (if used as a | |
| // lvalue). The conversion is achieved by specializing and overloading a | |
| // couple of the Phoenix templates from the Phoenix expression composition | |
| // engine (see the end of this file). | |
| struct value_context | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef unused_type type; | |
| }; | |
| template <typename Env> | |
| unused_type | |
| eval(Env const& env) const | |
| { | |
| return unused; | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The eoi_getter is used to create the _eoi placeholder, which is a | |
| // Phoenix actor used to access the end of input iterator pointing to the | |
| // end of the underlying input sequence. | |
| // | |
| // This actor is invoked whenever the placeholder '_eoi' is used in a | |
| // lexer semantic action: | |
| // | |
| // lex::token_def<> identifier = "[a-zA-Z_][a-zA-Z0-9_]*"; | |
| // this->self = identifier | |
| // [ std::cout << construct_<std::string>(_end, _eoi) ]; | |
| // | |
| // The example shows how to use _eoi to print all remaining input after | |
| // matching a token 'identifier'. | |
| struct eoi_getter | |
| { | |
| typedef mpl::true_ no_nullary; | |
| template <typename Env> | |
| struct result | |
| { | |
| typedef typename | |
| remove_const< | |
| typename mpl::at_c<typename Env::args_type, 4>::type | |
| >::type | |
| context_type; | |
| typedef typename context_type::base_iterator_type const& type; | |
| }; | |
| template <typename Env> | |
| typename result<Env>::type | |
| eval(Env const& env) const | |
| { | |
| return fusion::at_c<4>(env.args()).get_eoi(); | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // '_start' and '_end' may be used to access the start and the end of | |
| // the matched sequence of the current token | |
| phoenix::actor<phoenix::argument<0> > const _start = phoenix::argument<0>(); | |
| phoenix::actor<phoenix::argument<1> > const _end = phoenix::argument<1>(); | |
| // We are reusing the placeholder '_pass' to access and change the pass | |
| // status of the current match (see support/argument.hpp for its | |
| // definition). | |
| using boost::spirit::_pass; | |
| // '_tokenid' may be used to access and change the tokenid of the current | |
| // token | |
| phoenix::actor<phoenix::argument<3> > const _tokenid = phoenix::argument<3>(); | |
| // '_val' may be used to access and change the token value of the current | |
| // token | |
| phoenix::actor<value_context> const _val = value_context(); | |
| // _state may be used to access and change the name of the current lexer | |
| // state | |
| phoenix::actor<state_context> const _state = state_context(); | |
| // '_eoi' may be used to access the end of input iterator of the input | |
| // stream used by the lexer to match tokens from | |
| phoenix::actor<eoi_getter> const _eoi = eoi_getter(); | |
| }}} | |
| /////////////////////////////////////////////////////////////////////////////// | |
| namespace boost { namespace phoenix | |
| { | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The specialization of as_actor_base<> below is needed to convert all | |
| // occurrences of _state in places where it's used as a rvalue into the | |
| // proper Phoenix actor (spirit::state_getter) accessing the lexer state. | |
| template<> | |
| struct as_actor_base<actor<spirit::lex::state_context> > | |
| { | |
| typedef spirit::lex::state_getter type; | |
| static spirit::lex::state_getter | |
| convert(actor<spirit::lex::state_context>) | |
| { | |
| return spirit::lex::state_getter(); | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The specialization of as_composite<> below is needed to convert all | |
| // assignments to _state (places where it's used as a lvalue) into the | |
| // proper Phoenix actor (spirit::state_setter) allowing to change the | |
| // lexer state. | |
| template <typename RHS> | |
| struct as_composite<assign_eval, actor<spirit::lex::state_context>, RHS> | |
| { | |
| // For an assignment to _state (a spirit::state_context actor), this | |
| // specialization makes Phoenix's compose() function construct a | |
| // spirit::state_setter actor from 1. the LHS, a spirit::state_getter | |
| // actor (due to the specialization of as_actor_base<> above), | |
| // and 2. the RHS actor. | |
| // This is why spirit::state_setter needs a constructor which takes | |
| // a dummy spirit::state_getter as its first argument in addition | |
| // to its real, second argument (the RHS actor). | |
| typedef spirit::lex::state_setter<typename as_actor<RHS>::type> type; | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The specialization of as_actor_base<> below is needed to convert all | |
| // occurrences of _val in places where it's used as a rvalue into the | |
| // proper Phoenix actor (spirit::value_getter) accessing the token value. | |
| template<> | |
| struct as_actor_base<actor<spirit::lex::value_context> > | |
| { | |
| typedef spirit::lex::value_getter type; | |
| static spirit::lex::value_getter | |
| convert(actor<spirit::lex::value_context>) | |
| { | |
| return spirit::lex::value_getter(); | |
| } | |
| }; | |
| /////////////////////////////////////////////////////////////////////////// | |
| // The specialization of as_composite<> below is needed to convert all | |
| // assignments to _val (places where it's used as a lvalue) into the | |
| // proper Phoenix actor (spirit::value_setter) allowing to change the | |
| // token value. | |
| template <typename RHS> | |
| struct as_composite<assign_eval, actor<spirit::lex::value_context>, RHS> | |
| { | |
| // For an assignment to _val (a spirit::value_context actor), this | |
| // specialization makes Phoenix's compose() function construct a | |
| // spirit::value_setter actor from 1. the LHS, a spirit::value_getter | |
| // actor (due to the specialization of as_actor_base<> above), | |
| // and 2. the RHS actor. | |
| // This is why spirit::value_setter needs a constructor which takes | |
| // a dummy spirit::value_getter as its first argument in addition | |
| // to its real, second argument (the RHS actor). | |
| typedef spirit::lex::value_setter<typename as_actor<RHS>::type> type; | |
| }; | |
| }} | |
| #undef SPIRIT_DECLARE_ARG | |
| #endif | |