mapnik/src/expression.cpp
2015-06-16 12:49:16 +02:00

69 lines
2.3 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2015 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
// mapnik
#include <mapnik/expression.hpp>
#include <mapnik/config_error.hpp>
#include <mapnik/unicode.hpp>
#include <mapnik/expression_node_types.hpp>
#include <mapnik/expression_grammar.hpp>
// boost
#include <boost/spirit/include/qi.hpp>
namespace mapnik
{
expression_ptr parse_expression(std::string const& str)
{
static const expression_grammar<std::string::const_iterator> g;
boost::spirit::standard_wide::space_type space;
auto node = std::make_shared<expr_node>();
std::string::const_iterator itr = str.begin();
std::string::const_iterator end = str.end();
bool r = false;
try
{
r = boost::spirit::qi::phrase_parse(itr, end, g, space, *node);
}
catch (boost::spirit::qi::expectation_failure<std::string::const_iterator> const& ex)
{
// no need to show "boost::spirit::qi::expectation_failure" which is a std::runtime_error
throw config_error("Failed to parse expression: \"" + str + "\"");
}
catch (std::exception const& ex)
{
// show "Could not initialize ICU resources" from boost::regex which is a std::runtime_error
throw config_error(std::string(ex.what()) + " for expression: \"" + str + "\"");
}
if (r && itr == end)
{
return node;
}
else
{
throw config_error("Failed to parse expression: \"" + str + "\"");
}
}
}