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mapnik/src/expression.cpp
2022-11-10 15:57:38 +00:00

70 lines
2.5 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2021 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_x3.hpp>
namespace mapnik {
expression_ptr parse_expression(std::string const& str)
{
auto node = std::make_shared<expr_node>();
using boost::spirit::x3::ascii::space;
mapnik::transcoder const tr("utf8");
#if BOOST_VERSION >= 106700
auto parser = boost::spirit::x3::with<mapnik::grammar::transcoder_tag>(tr)[mapnik::grammar::expression];
#else
auto parser = boost::spirit::x3::with<mapnik::grammar::transcoder_tag>(std::ref(tr))[mapnik::grammar::expression];
#endif
bool r = false;
std::string::const_iterator itr = str.begin();
std::string::const_iterator const end = str.end();
try
{
r = boost::spirit::x3::phrase_parse(itr, end, parser, space, *node);
}
catch (boost::spirit::x3::expectation_failure<std::string::const_iterator> const& ex)
{
// no need to show "boost::spirit::x3::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 + "\"");
}
}
} // namespace mapnik