spirit/test/x3/iterator_check.cpp
Han Wang 766cc4c9b7 ForwardIterator -> ReadableIteratorConcept & ForwardTraversalConcept
The concept of ForwardIterator is flawed because it mixed 2 sets of concepts (value access and traversal) into 1 package.

http://www.boost.org/doc/libs/1_65_1/libs/iterator/doc/new-iter-concepts.html

It requires value_type (const)& as return type when dereference is applied, which is not mandatory in spirit parsing. A return type which is convertible to value_type is good enough. ReadableIteratorConcept and ForwardTraversalConcept should be what we need for the iterator check.

For example, the iterator of the range returned by boost::adaptors::transform(std::string, func) is normally not a ForwardIterator. But it fulfills ReadableIteratorConcept and ForwardTraversalConcept and should be able to be parsed by spirit.
2017-12-07 17:25:37 +01:00

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1.6 KiB
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/*=============================================================================
Copyright (c) 2001-2017 Joel de Guzman
Copyright (c) 2017 think-cell GmbH
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)
=============================================================================*/
#include <boost/detail/lightweight_test.hpp>
#include <boost/spirit/home/x3.hpp>
#include <boost/range/adaptor/transformed.hpp>
#include <iostream>
#include <string>
#include <functional>
int main()
{
using boost::adaptors::transform;
using boost::spirit::x3::raw;
using boost::spirit::x3::eps;
using boost::spirit::x3::eoi;
using boost::spirit::x3::upper;
using boost::spirit::x3::repeat;
using boost::spirit::x3::parse;
std::string input = "abcde";
std::function<char(char)> func = [](char c) {
return c < 'a' || 'z' < c ? c : static_cast<char>(c - 'a' + 'A');
};
auto const rng = transform(input, func);
{
std::string str;
BOOST_TEST((parse(boost::begin(rng), boost::end(rng), +upper >> eoi, str)));
BOOST_TEST(("ABCDE"==str));
}
{
boost::iterator_range<decltype(boost::begin(rng))> str;
BOOST_TEST((parse(boost::begin(rng), boost::end(rng), raw[+upper >> eoi], str)));
BOOST_TEST((boost::equal(std::string("ABCDE"), str)));
}
{
BOOST_TEST((parse(boost::begin(rng), boost::end(rng), (repeat(6)[upper] | repeat(5)[upper]) >> eoi)));
}
return boost::report_errors();
}