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Support lambda expressions in function_input_iterator

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This commit is contained in:
nekko1119 2015-12-28 02:45:49 +09:00
parent 711a0232f8
commit c09c8ca2b2
2 changed files with 22 additions and 4 deletions
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9
include/boost/iterator/function_input_iterator.hpp
View File

@ -17,6 +17,7 @@
#include <boost/iterator/iterator_facade.hpp> #include <boost/iterator/iterator_facade.hpp>
#include <boost/none.hpp> #include <boost/none.hpp>
#include <boost/optional/optional.hpp> #include <boost/optional/optional.hpp>
#include <boost/utility/result_of.hpp>
namespace boost { namespace boost {
@ -28,9 +29,9 @@ namespace iterators {
class function_input_iterator class function_input_iterator
: public iterator_facade< : public iterator_facade<
function_input_iterator<Function, Input>, function_input_iterator<Function, Input>,
typename Function::result_type, BOOST_DEDUCED_TYPENAME result_of<Function ()>::type,
single_pass_traversal_tag, single_pass_traversal_tag,
typename Function::result_type const & BOOST_DEDUCED_TYPENAME result_of<Function ()>::type const &
> >
{ {
public: public:
@ -46,7 +47,7 @@ namespace iterators {
++state; ++state;
} }
typename Function::result_type const & BOOST_DEDUCED_TYPENAME result_of<Function ()>::type const &
dereference() const { dereference() const {
return (value ? value : value = (*f)()).get(); return (value ? value : value = (*f)()).get();
} }
@ -58,7 +59,7 @@ namespace iterators {
private: private:
Function * f; Function * f;
Input state; Input state;
mutable optional<typename Function::result_type> value; mutable optional<BOOST_DEDUCED_TYPENAME result_of<Function ()>::type> value;
}; };
template <class Function, class Input> template <class Function, class Input>

17
test/function_input_iterator_test.cpp
View File

@ -96,6 +96,23 @@ int main(int argc, char * argv[])
assert(generated[i] == 42 + i); assert(generated[i] == 42 + i);
cout << "function iterator test with stateful function object successful." << endl; cout << "function iterator test with stateful function object successful." << endl;
#if !defined(BOOST_NO_CXX11_LAMBDAS) && !defined(BOOST_NO_CXX11_AUTO_DECLARATIONS)
// test the iterator with lambda expressions
int num = 42;
auto lambda_generator = [&num] { return num++; };
vector<int>().swap(generated);
copy(
boost::make_function_input_iterator(lambda_generator, 0),
boost::make_function_input_iterator(lambda_generator, 10),
back_inserter(generated)
);
assert(generated.size() == 10);
for(std::size_t i = 0; i != 10; ++i)
assert(generated[i] == 42 + i);
cout << "function iterator test with lambda expressions successful." << endl;
#endif // BOOST_NO_CXX11_LAMBDAS
return 0; return 0;
} }