spirit/example/lex/lexer_debug_support.cpp
2017-11-21 19:49:36 +03:00

110 lines
3.4 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)
// #define BOOST_SPIRIT_LEXERTL_DEBUG 1
#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/lex_lexertl.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
namespace lex = boost::spirit::lex;
namespace qi = boost::spirit::qi;
namespace phoenix = boost::phoenix;
///////////////////////////////////////////////////////////////////////////////
template <typename Lexer>
struct language_tokens : lex::lexer<Lexer>
{
language_tokens()
{
tok_float = "float";
tok_int = "int";
floatlit = "[0-9]+\\.[0-9]*";
intlit = "[0-9]+";
ws = "[ \t\n]+";
identifier = "[a-zA-Z_][a-zA-Z_0-9]*";
this->self = ws [lex::_pass = lex::pass_flags::pass_ignore];
this->self += tok_float | tok_int | floatlit | intlit | identifier;
this->self += lex::char_('=');
}
lex::token_def<> tok_float, tok_int;
lex::token_def<> ws;
lex::token_def<double> floatlit;
lex::token_def<int> intlit;
lex::token_def<> identifier;
};
///////////////////////////////////////////////////////////////////////////////
template <typename Iterator>
struct language_grammar : qi::grammar<Iterator>
{
template <typename Lexer>
language_grammar(language_tokens<Lexer> const& tok)
: language_grammar::base_type(declarations)
{
declarations = +number;
number =
tok.tok_float >> tok.identifier >> '=' >> tok.floatlit
| tok.tok_int >> tok.identifier >> '=' >> tok.intlit
;
declarations.name("declarations");
number.name("number");
debug(declarations);
debug(number);
}
qi::rule<Iterator> declarations;
qi::rule<Iterator> number;
};
///////////////////////////////////////////////////////////////////////////////
int main()
{
// iterator type used to expose the underlying input stream
typedef std::string::iterator base_iterator_type;
// lexer type
typedef lex::lexertl::actor_lexer<
lex::lexertl::token<
base_iterator_type, boost::mpl::vector2<double, int>
> > lexer_type;
// iterator type exposed by the lexer
typedef language_tokens<lexer_type>::iterator_type iterator_type;
// now we use the types defined above to create the lexer and grammar
// object instances needed to invoke the parsing process
language_tokens<lexer_type> tokenizer; // Our lexer
language_grammar<iterator_type> g (tokenizer); // Our parser
// Parsing is done based on the token stream, not the character
// stream read from the input.
std::string str ("float f = 3.4\nint i = 6\n");
base_iterator_type first = str.begin();
bool r = lex::tokenize_and_parse(first, str.end(), tokenizer, g);
if (r) {
std::cout << "-------------------------\n";
std::cout << "Parsing succeeded\n";
std::cout << "-------------------------\n";
}
else {
std::string rest(first, str.end());
std::cout << "-------------------------\n";
std::cout << "Parsing failed\n";
std::cout << "stopped at: \"" << rest << "\"\n";
std::cout << "-------------------------\n";
}
std::cout << "Bye... :-) \n\n";
return 0;
}