boost/libs/spirit/example/x3/calc9/error_handler.hpp

/*=============================================================================
    Copyright (c) 2001-2014 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_X3_CALC9_ERROR_HANDLER_HPP)
#define BOOST_SPIRIT_X3_CALC9_ERROR_HANDLER_HPP

#include <boost/spirit/home/x3.hpp>
#include <boost/spirit/home/x3/support/utility/error_reporting.hpp>
#include <boost/spirit/home/x3/support/ast/position_tagged.hpp>
#include "expression.hpp"
#include "statement.hpp"

namespace client { namespace parser
{
    namespace x3 = boost::spirit::x3;
    
    ////////////////////////////////////////////////////////////////////////////
    //  Our error handler
    ////////////////////////////////////////////////////////////////////////////
    template <typename Iterator>
    using error_handler = x3::error_handler<Iterator>;

    // tag used to get our error handler from the context
    struct error_handler_tag;
    
    struct error_handler_base
    {
        template <typename Iterator, typename Exception, typename Context>
        x3::error_handler_result on_error(
            Iterator& first, Iterator const& last
          , Exception const& x, Context const& context)
        {
            std::string message = "Error! Expecting: " + x.which() + " here:";
            auto& error_handler = x3::get<error_handler_tag>(context).get();
            error_handler(x.where(), message);
            return x3::error_handler_result::fail;
        }
    };
}}

#endif