| // Copyright (c) 2001-2009 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) |
| |
| #if !defined(BOOST_SPIRIT_WHAT_MAY_04_2007_0116PM) |
| #define BOOST_SPIRIT_WHAT_MAY_04_2007_0116PM |
| |
| #include <boost/spirit/home/karma/meta_grammar.hpp> |
| #include <boost/mpl/assert.hpp> |
| #include <string> |
| |
| namespace boost { namespace spirit { namespace karma |
| { |
| template <typename Expr> |
| inline std::string what(Expr const& xpr) |
| { |
| typedef spirit::traits::is_component<karma::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_generator, ()); |
| |
| typedef typename |
| spirit::result_of::as_component<karma::domain, Expr>::type |
| component; |
| typedef typename component::director director; |
| |
| component c = spirit::as_component(karma::domain(), xpr); |
| return director::what(c, unused); |
| } |
| }}} |
| |
| #endif |
| |