boost/spirit/home/x3/support/utility/error_reporting.hpp
/*=============================================================================
Copyright (c) 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_ERROR_REPORTING_MAY_19_2014_00405PM)
#define BOOST_SPIRIT_X3_ERROR_REPORTING_MAY_19_2014_00405PM
#ifndef BOOST_SPIRIT_X3_NO_FILESYSTEM
#include <boost/filesystem/path.hpp>
#endif
#include <boost/locale/encoding_utf.hpp>
#include <boost/spirit/home/x3/support/ast/position_tagged.hpp>
#include <ostream>
// Clang-style error handling utilities
namespace boost { namespace spirit { namespace x3
{
// tag used to get our error handler from the context
struct error_handler_tag;
template <typename Iterator>
class error_handler
{
public:
typedef Iterator iterator_type;
error_handler(
Iterator first, Iterator last, std::ostream& err_out
, std::string file = "", int tabs = 4)
: err_out(err_out)
, file(file)
, tabs(tabs)
, pos_cache(first, last) {}
typedef void result_type;
void operator()(Iterator err_pos, std::string const& error_message) const;
void operator()(Iterator err_first, Iterator err_last, std::string const& error_message) const;
void operator()(position_tagged pos, std::string const& message) const
{
auto where = pos_cache.position_of(pos);
(*this)(where.begin(), where.end(), message);
}
template <typename AST>
void tag(AST& ast, Iterator first, Iterator last)
{
return pos_cache.annotate(ast, first, last);
}
boost::iterator_range<Iterator> position_of(position_tagged pos) const
{
return pos_cache.position_of(pos);
}
position_cache<std::vector<Iterator>> const& get_position_cache() const
{
return pos_cache;
}
private:
void print_file_line(std::size_t line) const;
void print_line(Iterator line_start, Iterator last) const;
void print_indicator(Iterator& line_start, Iterator last, char ind) const;
void skip_whitespace(Iterator& err_pos, Iterator last) const;
void skip_non_whitespace(Iterator& err_pos, Iterator last) const;
Iterator get_line_start(Iterator first, Iterator pos) const;
std::size_t position(Iterator i) const;
std::ostream& err_out;
std::string file;
int tabs;
position_cache<std::vector<Iterator>> pos_cache;
};
template <typename Iterator>
void error_handler<Iterator>::print_file_line(std::size_t line) const
{
if (file != "")
{
#ifdef BOOST_SPIRIT_X3_NO_FILESYSTEM
err_out << "In file " << file << ", ";
#else
namespace fs = boost::filesystem;
err_out << "In file " << fs::path(file).generic_string() << ", ";
#endif
}
else
{
err_out << "In ";
}
err_out << "line " << line << ':' << std::endl;
}
template <typename Iterator>
void error_handler<Iterator>::print_line(Iterator start, Iterator last) const
{
auto end = start;
while (end != last)
{
auto c = *end;
if (c == '\r' || c == '\n')
break;
else
++end;
}
typedef typename std::iterator_traits<Iterator>::value_type char_type;
std::basic_string<char_type> line{start, end};
err_out << locale::conv::utf_to_utf<char>(line) << std::endl;
}
template <typename Iterator>
void error_handler<Iterator>::print_indicator(Iterator& start, Iterator last, char ind) const
{
for (; start != last; ++start)
{
auto c = *start;
if (c == '\r' || c == '\n')
break;
else if (c == '\t')
for (int i = 0; i < tabs; ++i)
err_out << ind;
else
err_out << ind;
}
}
template <typename Iterator>
void error_handler<Iterator>::skip_whitespace(Iterator& err_pos, Iterator last) const
{
// make sure err_pos does not point to white space
while (err_pos != last)
{
char c = *err_pos;
if (std::isspace(c))
++err_pos;
else
break;
}
}
template <typename Iterator>
void error_handler<Iterator>::skip_non_whitespace(Iterator& err_pos, Iterator last) const
{
// make sure err_pos does not point to white space
while (err_pos != last)
{
char c = *err_pos;
if (std::isspace(c))
break;
else
++err_pos;
}
}
template <class Iterator>
inline Iterator error_handler<Iterator>::get_line_start(Iterator first, Iterator pos) const
{
Iterator latest = first;
for (Iterator i = first; i != pos; ++i)
if (*i == '\r' || *i == '\n')
latest = i;
return latest;
}
template <typename Iterator>
std::size_t error_handler<Iterator>::position(Iterator i) const
{
std::size_t line { 1 };
typename std::iterator_traits<Iterator>::value_type prev { 0 };
for (Iterator pos = pos_cache.first(); pos != i; ++pos) {
auto c = *pos;
switch (c) {
case '\n':
if (prev != '\r') ++line;
break;
case '\r':
++line;
break;
default:
break;
}
prev = c;
}
return line;
}
template <typename Iterator>
void error_handler<Iterator>::operator()(
Iterator err_pos, std::string const& error_message) const
{
Iterator first = pos_cache.first();
Iterator last = pos_cache.last();
// make sure err_pos does not point to white space
skip_whitespace(err_pos, last);
print_file_line(position(err_pos));
err_out << error_message << std::endl;
Iterator start = get_line_start(first, err_pos);
if (start != first)
++start;
print_line(start, last);
print_indicator(start, err_pos, '_');
err_out << "^_" << std::endl;
}
template <typename Iterator>
void error_handler<Iterator>::operator()(
Iterator err_first, Iterator err_last, std::string const& error_message) const
{
Iterator first = pos_cache.first();
Iterator last = pos_cache.last();
// make sure err_pos does not point to white space
skip_whitespace(err_first, last);
print_file_line(position(err_first));
err_out << error_message << std::endl;
Iterator start = get_line_start(first, err_first);
if (start != first)
++start;
print_line(start, last);
print_indicator(start, err_first, ' ');
print_indicator(start, err_last, '~');
err_out << " <<-- Here" << std::endl;
}
}}}
#endif
