Subject: [Boost-bugs] [Boost C++ Libraries] #11274: coroutine's iterators don't fully comply
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-05-07 08:35:52
#11274: coroutine's iterators don't fully comply
---------------------------------------------+-----------------------
Reporter: Akim Demaille <akim.demaille@…> | Owner: olli
Type: Bugs | Status: new
Milestone: To Be Determined | Component: coroutine
Version: Boost 1.58.0 | Severity: Problem
Keywords: |
---------------------------------------------+-----------------------
Hi!
The following example fails to compile cleanly. I use a boost range
adaptor to slice an "endless" coroutine, used as a generator: source |
strided(10).
{{{
// begin:header
#include <iostream>
#include <boost/coroutine/coroutine.hpp>
#include <boost/range/adaptor/strided.hpp>
using namespace boost::adaptors;
using coro_t = boost::coroutines::asymmetric_coroutine<int>;
// end:header
// begin:func
void fibo(coro_t::push_type& sink)
{
int first = 1, second = 1;
sink(first);
sink(second);
for (;;)
{
int third = first + second;
first = second;
second = third;
sink(third);
}
};
// end:func
// begin:main
int main()
{
auto source = coro_t::pull_type{fibo};
for (auto i : source | strided(10))
std::cout << i << " ";
std::cout << '\n';
}
// end:main
// CXXFLAGS: -lboost_coroutine-mt -lboost_system-mt
}}}
It results in:
{{{
clang++ -stdlib=libc++ -isystem/opt/local/include -std=c++11 -Wall -Wextra
-ggdb -L/opt/local/lib -lboost_coroutine-mt -lboost_system-mt -o
6-concurrency/coroutine.exe 6-concurrency/coroutine.cc &&
6-concurrency/coroutine.exe </dev/null >6-concurrency/coroutine.log.tmp
2>&1 && mv 6-concurrency/coroutine.log.tmp 6-concurrency/coroutine.log &&
{ test "1" != 1 || cat 6-concurrency/coroutine.log; }
In file included from 6-concurrency/coroutine.cc:3:
In file included from /opt/local/include/boost/coroutine/coroutine.hpp:10:
In file included from
/opt/local/include/boost/coroutine/asymmetric_coroutine.hpp:17:
In file included from /opt/local/include/boost/range.hpp:18:
In file included from /opt/local/include/boost/range/functions.hpp:20:
In file included from /opt/local/include/boost/range/size.hpp:21:
In file included from /opt/local/include/boost/range/size_type.hpp:20:
In file included from /opt/local/include/boost/range/concepts.hpp:20:
In file included from
/opt/local/include/boost/iterator/iterator_concepts.hpp:10:
/opt/local/include/boost/iterator/iterator_categories.hpp:119:60: error:
no type named
'iterator_category' in
'std::__1::iterator_traits<boost::coroutines::pull_coroutine<int>::const_iterator>'
typename
boost::detail::iterator_traits<Iterator>::iterator_category
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/opt/local/include/boost/range/adaptor/strided.hpp:606:26: note: in
instantiation of
template class
'boost::iterators::iterator_traversal<boost::coroutines::pull_coroutine<int>::const_iterator>'
requested here
typename iterator_traversal<
^
/opt/local/include/boost/range/adaptor/strided.hpp:660:16: note: in
instantiation of
default argument for 'strided_range<const
boost::coroutines::pull_coroutine<int>
>' required here
inline strided_range<const Rng>
^~~~~~~~~~~~~~~~~~~~~~~~
6-concurrency/coroutine.cc:30:24: note: while substituting deduced
template arguments
into function template 'operator|' [with Rng =
boost::coroutines::pull_coroutine<int>, Difference = int]
for (auto i : source | strided(10))
^
In file included from 6-concurrency/coroutine.cc:4:
/opt/local/include/boost/range/adaptor/strided.hpp:627:21: error: no
matching function
for call to 'make_begin_strided_iterator'
range_detail::make_begin_strided_iterator(
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/opt/local/include/boost/range/adaptor/strided.hpp:656:20: note: in
instantiation of
function template specialization
'boost::range_detail::strided_range<boost::coroutines::pull_coroutine<int>,
boost::iterators::single_pass_traversal_tag>::strided_range<int>'
requested here
return strided_range<Rng>(stride.val, rng);
^
6-concurrency/coroutine.cc:30:24: note: in instantiation of function
template
specialization
'boost::range_detail::operator|<boost::coroutines::pull_coroutine<int>,
int>'
requested here
for (auto i : source | strided(10))
^
/opt/local/include/boost/range/adaptor/strided.hpp:412:9: note: candidate
function
[with Rng = boost::coroutines::pull_coroutine<int>, Difference =
int] not
viable: no known conversion from 'typename
iterator_traversal<typename
range_iterator<pull_coroutine<int> >::type>::type' (aka
'boost::iterators::single_pass_traversal_tag') to
'boost::iterators::forward_traversal_tag' for 3rd argument
make_begin_strided_iterator(
^
/opt/local/include/boost/range/adaptor/strided.hpp:476:9: note: candidate
function
[with Rng = boost::coroutines::pull_coroutine<int>, Difference =
int] not
viable: no known conversion from 'typename
iterator_traversal<typename
range_iterator<pull_coroutine<int> >::type>::type' (aka
'boost::iterators::single_pass_traversal_tag') to
'boost::iterators::bidirectional_traversal_tag' for 3rd argument
make_begin_strided_iterator(
^
/opt/local/include/boost/range/adaptor/strided.hpp:544:9: note: candidate
function
[with Rng = boost::coroutines::pull_coroutine<int>, Difference =
int] not
viable: no known conversion from 'typename
iterator_traversal<typename
range_iterator<pull_coroutine<int> >::type>::type' (aka
'boost::iterators::single_pass_traversal_tag') to
'boost::iterators::random_access_traversal_tag' for 3rd argument
make_begin_strided_iterator(
^
/opt/local/include/boost/range/adaptor/strided.hpp:428:9: note: candidate
function
[with Rng = boost::coroutines::pull_coroutine<int>, Difference =
int] not
viable: no known conversion from 'typename
iterator_traversal<typename
range_iterator<pull_coroutine<int> >::type>::type' (aka
'boost::iterators::single_pass_traversal_tag') to
'boost::iterators::forward_traversal_tag' for 3rd argument
make_begin_strided_iterator(
^
/opt/local/include/boost/range/adaptor/strided.hpp:494:9: note: candidate
function
[with Rng = boost::coroutines::pull_coroutine<int>, Difference =
int] not
viable: no known conversion from 'typename
iterator_traversal<typename
range_iterator<pull_coroutine<int> >::type>::type' (aka
'boost::iterators::single_pass_traversal_tag') to
'boost::iterators::bidirectional_traversal_tag' for 3rd argument
make_begin_strided_iterator(
^
/opt/local/include/boost/range/adaptor/strided.hpp:560:9: note: candidate
function
[with Rng = boost::coroutines::pull_coroutine<int>, Difference =
int] not
viable: no known conversion from 'typename
iterator_traversal<typename
range_iterator<pull_coroutine<int> >::type>::type' (aka
'boost::iterators::single_pass_traversal_tag') to
'boost::iterators::random_access_traversal_tag' for 3rd argument
make_begin_strided_iterator(
^
2 errors generated.
make[1]: *** [6-concurrency/coroutine.log] Error 1
make[1]: Leaving directory `/Users/akim/src/lrde/cours/cxxa'
make: *** [all] Error 2
Compilation exited abnormally with code 2 at Thu May 7 10:29:24
}}}
It seems to me that the problem is that const_iterator does not define
iterator_category, and it should. Maybe Boost.Coroutine should use
Boost.IteratorFacade to define its iterators?
-- Ticket URL: <https://svn.boost.org/trac/boost/ticket/11274> Boost C++ Libraries <http://www.boost.org/> Boost provides free peer-reviewed portable C++ source libraries.
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