| /*============================================================================= |
| Copyright (c) 2001-2007 Joel de Guzman |
| |
| 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_WHAT_APRIL_21_2007_0732AM) |
| #define BOOST_SPIRIT_WHAT_APRIL_21_2007_0732AM |
| |
| #include <boost/spirit/home/qi/meta_grammar.hpp> |
| #include <boost/mpl/assert.hpp> |
| #include <string> |
| |
| namespace boost { namespace spirit { namespace qi |
| { |
| template <typename Expr> |
| inline std::string what(Expr const& xpr) |
| { |
| typedef spirit::traits::is_component<qi::domain, Expr> is_component; |
| |
| // report invalid expression error as early as possible |
| BOOST_MPL_ASSERT_MSG( |
| is_component::value, |
| xpr_is_not_convertible_to_a_parser, ()); |
| |
| typedef typename result_of::as_component<qi::domain, Expr>::type component; |
| typedef typename component::director director; |
| component c = spirit::as_component(qi::domain(), xpr); |
| return director::what(c, unused); |
| } |
| }}} |
| |
| #endif |
| |