spirit/test/lex/lexer_state_switcher.cpp
2018-10-01 02:16:04 +03:00

67 lines
2.2 KiB
C++

// Copyright (c) 2001-2011 Hartmut Kaiser
//
// 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)
#include <boost/mpl/print.hpp>
#include <boost/detail/lightweight_test.hpp>
#include <boost/spirit/include/phoenix_object.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
#include <boost/spirit/include/lex_lexertl.hpp>
///////////////////////////////////////////////////////////////////////////////
// Token definition
///////////////////////////////////////////////////////////////////////////////
template <typename Lexer>
struct switch_state_tokens : boost::spirit::lex::lexer<Lexer>
{
// define tokens and associate them with the lexer
switch_state_tokens()
{
namespace phoenix = boost::phoenix;
using boost::spirit::lex::_state;
identifier = "[a-zA-Z_][a-zA-Z0-9_]*";
this->self = identifier [ phoenix::ref(state_) = _state ];
integer = "[0-9]+";
this->self("INT") = integer [ _state = "INITIAL" ];
}
std::string state_;
boost::spirit::lex::token_def<> identifier, integer;
};
///////////////////////////////////////////////////////////////////////////////
int main()
{
using namespace boost::spirit;
using namespace boost::spirit::lex;
typedef std::string::iterator base_iterator_type;
typedef boost::spirit::lex::lexertl::token<base_iterator_type> token_type;
typedef boost::spirit::lex::lexertl::actor_lexer<token_type> lexer_type;
{
switch_state_tokens<lexer_type> lex;
{
// verify whether using _state as an rvalue works
std::string input("abc123");
base_iterator_type first = input.begin();
BOOST_TEST(boost::spirit::lex::tokenize(first, input.end(), lex) &&
lex.state_ == "INITIAL");
}
{
// verify whether using _state as an lvalue works
std::string input("123abc123");
base_iterator_type first = input.begin();
BOOST_TEST(boost::spirit::lex::tokenize(first, input.end(), lex, "INT") &&
lex.state_ == "INITIAL");
}
}
return boost::report_errors();
}