Implement `std::experimental::ostream_joiner`

[mclow.lists]

Summary

This is part of the Library Fundamentals 2 TS

[EricWF]

• Please add the header to test/libcxx/double_include.sh.cpp
• Please add a _LIBCPP_VERSION test in test/libcxx/experimental/iterator
• The ostream_joiner type and it's members should be given visibility attributes.

include/experimental/iterator

62 ↗

(On Diff #46059)

Wrong namespace. This gives std::experimental::fundamentals_v2. This brings up the bigger question of how we want to manage two TS's.

64 ↗

(On Diff #46059)

Is _Delim allowed to be a reference? We might get better diagnostics if we static assert some requirements on _Delim.

85 ↗

(On Diff #46059)

People are going to try and use this as an assignment operator. We either need to static assert in the body, or disable the operator entirely.
I'm not sure which is better. It depends on if we want a generated operator=.

94 ↗

(On Diff #46059)

Unrelated note: Are we ever going to stop guarding noexcept behind a macro?

test/std/experimental/iterator/nothing_to_do.pass.cpp

2

LIT will only emit a warning if all sub directories are empty as well. Do we need this file for testit^

test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp

36

Can you test that joiner has the expected type?

test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp

38

Nice test. Is there a reason to pass the delimiter as const here? It seems equally valid that the mutating delimiter has a non-const operator<<.

[EricWF]

include/experimental/iterator

85 ↗

(On Diff #46059)

Disregard the comment above. It's not possible to call this with an instance of ostream_joiner. I thought it might be possible like it is with constructors.

[mclow.lists]

include/experimental/iterator

62 ↗

(On Diff #46059)

I think that the right thing is to flip all the LFTS over to v2.

94 ↗

(On Diff #46059)

Maybe. Depends on how much work it turns out to be.

I don't want to make that decision here, though.

test/std/experimental/iterator/nothing_to_do.pass.cpp

2

Well, if anyone was still running testit, yes.
But it's a nice simple test. Does including the header file actually work?

See test/std/experimental/optional or string_view for similar tests.

test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp

36

Sure.

test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp

38

I'll add that as well.

[mclow.lists]

Addressed Eric's comments. (at least some of them)

[EricWF]

One last thing. The spec implicitly defines the copy/move/assignment operators for "ostream_joiner" by making "_Delim" an exposition only member. Essentially "ostream_joiner" should only copy/moveable if "_Delim" is. I think we should add tests that ensure we actually follow this behavior.

test/std/experimental/iterator/nothing_to_do.pass.cpp

3

Maybe call it "include_header.pass.cpp" then.

[mclow.lists]

Add the tests that Eric suggested. Had to toss in a decay.

[EricWF]

LGTM.

[mclow.lists]

Landed as r259014 and r259015.

test/std/experimental/iterator/nothing_to_do.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include <experimental/iterator>
+
+int main () {}

test/std/experimental/iterator/ostream.joiner/ostream.joiner.cons/ostream_joiner.cons.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/iterator>
+//
+// template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+//   class ostream_joiner;
+//
+//     ostream_joiner(ostream_type& __os, _Delim&& __d);
+//     ostream_joiner(ostream_type& __os, const _Delim& __d);
+
+#include <experimental/iterator>
+#include <iostream>
+#include <string>
+
+#include "test_macros.h"
+
+namespace exp = std::experimental;
+
+int main () {
+  const char eight = '8';
+  const std::string nine = "9";
+  const std::wstring ten = L"10";
+  const int eleven = 11;
+
+//  Narrow streams w/rvalues
+  { exp::ostream_joiner<char>         oj(std::cout, '8'); } 
+  { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9")); } 
+  { exp::ostream_joiner<std::wstring> oj(std::cout, std::wstring(L"10")); } 
+  { exp::ostream_joiner<int>          oj(std::cout, 11); } 
+
+//  Narrow streams w/lvalues
+  { exp::ostream_joiner<char>         oj(std::cout, eight); } 
+  { exp::ostream_joiner<std::string>  oj(std::cout, nine); } 
+  { exp::ostream_joiner<std::wstring> oj(std::cout, ten); } 
+  { exp::ostream_joiner<int>          oj(std::cout, eleven); } 
+
+//  Wide streams w/rvalues
+  { exp::ostream_joiner<char, wchar_t>         oj(std::wcout, '8'); } 
+  { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9")); } 
+  { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); } 
+  { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11); } 
+
+//  Wide streams w/lvalues
+  { exp::ostream_joiner<char, wchar_t>         oj(std::wcout, eight); } 
+  { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, nine); } 
+  { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, ten); } 
+  { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, eleven); } 
+
+  }

test/std/experimental/iterator/ostream.joiner/ostream.joiner.creation/make_ostream_joiner.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/iterator>
+//
+// template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+//   class ostream_joiner;
+//
+//   template <class _CharT, class _Traits, class _Delim>
+//   ostream_joiner<typename decay<_Delim>::type, _CharT, _Traits>
+//   make_ostream_joiner(basic_ostream<_CharT, _Traits>& __os, _Delim && __d);
+//
+
+#include <experimental/iterator>
+#include <iostream>
+#include <sstream>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+
+namespace exp = std::experimental;
+
+template <class Delim, class Iter, class CharT = char, class Traits = std::char_traits<CharT>>
+void test (Delim &&d, Iter first, Iter last, const CharT *expected ) {
+    std::basic_stringstream<CharT, Traits> sstream;
+    auto joiner = exp::make_ostream_joiner(sstream, d);
+    typedef exp::ostream_joiner<typename std::decay<Delim>::type, CharT, Traits> Joiner;
+    static_assert((std::is_same<decltype(joiner), Joiner>::value), "" );
+    while (first != last)
+        joiner = *first++;
+    assert(sstream.str() == expected);
+    }
+
+int main () {
+    const char chars[] = "0123456789";
+    const int  ints [] = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
+
+//  There are more of these tests in another file.
+//  This is just to make sure that the ostream_joiner is created correctly
+    test('X', chars, chars+10, "0X1X2X3X4X5X6X7X8X9");
+    test('x', ints,  ints+10,  "10x11x12x13x14x15x16x17x18x19");
+    test("Z", chars, chars+10, "0Z1Z2Z3Z4Z5Z6Z7Z8Z9");
+    test("z", ints,  ints+10,  "10z11z12z13z14z15z16z17z18z19");
+    }

test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.assign.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/iterator>
+//
+// template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+//   class ostream_joiner;
+//
+//   template<typename T>
+//   ostream_joiner & operator=(const T&)
+//
+
+#include <experimental/iterator>
+#include <iostream>
+#include <sstream>
+#include <cassert>
+
+#include "test_macros.h"
+#include "test_iterators.h"
+
+struct mutating_delimiter {
+  mutating_delimiter(char c = ' ') : c_(c) {}
+  char get () const { return c_++; }
+  mutable char c_;
+  };
+
+template<class _CharT, class _Traits>
+std::basic_ostream<_CharT, _Traits>&
+operator<<(std::basic_ostream<_CharT, _Traits>& os, const mutating_delimiter &d)
+{ return os << d.get(); }
+
+
+struct mutating_delimiter2 { // same as above, w/o the const and the mutable
+  mutating_delimiter2(char c = ' ') : c_(c) {}
+  char get () { return c_++; }
+  char c_;
+  };
+
+template<class _CharT, class _Traits>
+std::basic_ostream<_CharT, _Traits>&
+operator<<(std::basic_ostream<_CharT, _Traits>& os, mutating_delimiter2 &d)
+{ return os << d.get(); }
+
+
+namespace exp = std::experimental;
+
+template <class Delim, class Iter, class CharT = char, class Traits = std::char_traits<CharT>>
+void test (Delim &&d, Iter first, Iter last, const CharT *expected ) {
+  typedef exp::ostream_joiner<typename std::decay<Delim>::type, CharT, Traits> Joiner;
+
+  static_assert((std::is_copy_constructible<Joiner>::value == std::is_copy_constructible<typename std::decay<Delim>::type>::value), "" );
+  static_assert((std::is_move_constructible<Joiner>::value == std::is_move_constructible<typename std::decay<Delim>::type>::value), "" );
+  static_assert((std::is_copy_assignable<Joiner>   ::value == std::is_copy_assignable<typename std::decay<Delim>::type>   ::value), "" );
+  static_assert((std::is_move_assignable<Joiner>   ::value == std::is_move_assignable<typename std::decay<Delim>::type>   ::value), "" );
+
+  std::basic_stringstream<CharT, Traits> sstream;
+  Joiner joiner(sstream, d);
+  while (first != last)
+    *joiner++ = *first++;
+  assert(sstream.str() == expected);
+  }
+
+int main () {
+{
+  const char chars[] = "0123456789";
+  const int  ints [] = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
+
+  test('X', chars, chars+10, "0X1X2X3X4X5X6X7X8X9");
+  test('x',  ints,  ints+10, "10x11x12x13x14x15x16x17x18x19");
+  test('X', input_iterator<const char*>(chars),         input_iterator<const char*>(chars+10),         "0X1X2X3X4X5X6X7X8X9");
+  test('x', input_iterator<const int*>(ints),           input_iterator<const int*>(ints+10),           "10x11x12x13x14x15x16x17x18x19");
+  test('X', forward_iterator<const char*>(chars),       forward_iterator<const char*>(chars+10),       "0X1X2X3X4X5X6X7X8X9");
+  test('x', forward_iterator<const int*>(ints),         forward_iterator<const int*>(ints+10),         "10x11x12x13x14x15x16x17x18x19");
+  test('X', random_access_iterator<const char*>(chars), random_access_iterator<const char*>(chars+10), "0X1X2X3X4X5X6X7X8X9");
+  test('x', random_access_iterator<const int*>(ints),   random_access_iterator<const int*>(ints+10),   "10x11x12x13x14x15x16x17x18x19");
+
+  test("Z", chars, chars+10, "0Z1Z2Z3Z4Z5Z6Z7Z8Z9");
+  test("z", ints,  ints+10,  "10z11z12z13z14z15z16z17z18z19");
+
+  test<char, const char *, wchar_t> ('X', chars, chars+10, L"0X1X2X3X4X5X6X7X8X9");
+  test<char, const int *,  wchar_t> ('x',  ints,  ints+10, L"10x11x12x13x14x15x16x17x18x19");
+//  test<char, const char *, char16_t>('X', chars, chars+10, u"0X1X2X3X4X5X6X7X8X9");
+//  test<char, const int *,  char16_t>('x',  ints,  ints+10, u"10x11x12x13x14x15x16x17x18x19");
+//  test<char, const char *, char32_t>('X', chars, chars+10, U"0X1X2X3X4X5X6X7X8X9");
+//  test<char, const int *,  char32_t>('x',  ints,  ints+10, U"10x11x12x13x14x15x16x17x18x19");
+
+  test(mutating_delimiter(),  chars, chars+10, "0 1!2\"3#4$5%6&7'8(9");
+  test(mutating_delimiter2(), chars, chars+10, "0 1!2\"3#4$5%6&7'8(9");
+  }
+  
+  {
+  const wchar_t chars[] = L"0123456789";
+  const int  ints [] = { 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 };
+  test(L'X', chars, chars+10, L"0X1X2X3X4X5X6X7X8X9");
+  test(L'x',  ints,  ints+10, L"10x11x12x13x14x15x16x17x18x19");
+  test(L'X', input_iterator<const wchar_t*>(chars),         input_iterator<const wchar_t*>(chars+10),         L"0X1X2X3X4X5X6X7X8X9");
+  test(L'x', input_iterator<const int*>(ints),              input_iterator<const int*>(ints+10),              L"10x11x12x13x14x15x16x17x18x19");
+  test(L'X', forward_iterator<const wchar_t*>(chars),       forward_iterator<const wchar_t*>(chars+10),       L"0X1X2X3X4X5X6X7X8X9");
+  test(L'x', forward_iterator<const int*>(ints),            forward_iterator<const int*>(ints+10),            L"10x11x12x13x14x15x16x17x18x19");
+  test(L'X', random_access_iterator<const wchar_t*>(chars), random_access_iterator<const wchar_t*>(chars+10), L"0X1X2X3X4X5X6X7X8X9");
+  test(L'x', random_access_iterator<const int*>(ints),      random_access_iterator<const int*>(ints+10),      L"10x11x12x13x14x15x16x17x18x19");
+
+  test(L"Z", chars, chars+10, L"0Z1Z2Z3Z4Z5Z6Z7Z8Z9");
+  test(L"z", ints,  ints+10,  L"10z11z12z13z14z15z16z17z18z19");
+
+  test<char, const wchar_t *, wchar_t> ('X', chars, chars+10, L"0X1X2X3X4X5X6X7X8X9");
+  test<char, const int *,  wchar_t>    ('x',  ints,  ints+10, L"10x11x12x13x14x15x16x17x18x19");
+
+  test(mutating_delimiter(), chars, chars+10, L"0 1!2\"3#4$5%6&7'8(9");
+  }
+
+}

test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.postincrement.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/iterator>
+//
+// template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+//   class ostream_joiner;
+//
+//   ostream_joiner & operator++(int) noexcept
+//     returns *this;
+
+#include <experimental/iterator>
+#include <iostream>
+#include <cassert>
+
+#include "test_macros.h"
+
+namespace exp = std::experimental;
+
+template <class Delim, class CharT, class Traits>
+void test ( exp::ostream_joiner<Delim, CharT, Traits> &oj ) {
+    static_assert((noexcept(oj++)), "" );
+    exp::ostream_joiner<Delim, CharT, Traits> &ret = oj++;
+    assert( &ret == &oj );
+    }
+
+int main () {
+
+    { exp::ostream_joiner<char>         oj(std::cout, '8');                 test(oj); }
+    { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9"));    test(oj); }
+    { exp::ostream_joiner<std::wstring> oj(std::cout, std::wstring(L"10")); test(oj); }
+    { exp::ostream_joiner<int>          oj(std::cout, 11);                  test(oj); }
+
+    { exp::ostream_joiner<char, wchar_t>         oj(std::wcout, '8');                 test(oj); }
+    { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9"));    test(oj); }
+    { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); test(oj); }
+    { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11);                  test(oj); }
+    }

test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.pretincrement.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/iterator>
+//
+// template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+//   class ostream_joiner;
+//
+//   ostream_joiner & operator++() noexcept
+//     returns *this;
+
+#include <experimental/iterator>
+#include <iostream>
+#include <cassert>
+
+#include "test_macros.h"
+
+namespace exp = std::experimental;
+
+template <class Delim, class CharT, class Traits>
+void test ( exp::ostream_joiner<Delim, CharT, Traits> &oj ) {
+    static_assert((noexcept(++oj)), "" );
+    exp::ostream_joiner<Delim, CharT, Traits> &ret = ++oj;
+    assert( &ret == &oj );
+    }
+
+int main () {
+
+    { exp::ostream_joiner<char>         oj(std::cout, '8');                 test(oj); }
+    { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9"));    test(oj); }
+    { exp::ostream_joiner<std::wstring> oj(std::cout, std::wstring(L"10")); test(oj); }
+    { exp::ostream_joiner<int>          oj(std::cout, 11);                  test(oj); }
+
+    { exp::ostream_joiner<char, wchar_t>         oj(std::wcout, '8');                 test(oj); }
+    { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9"));    test(oj); }
+    { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); test(oj); }
+    { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11);                  test(oj); }
+    }

test/std/experimental/iterator/ostream.joiner/ostream.joiner.ops/ostream_joiner.op.star.pass.cpp

+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11
+
+// <experimental/iterator>
+//
+// template <class _Delim, class _CharT = char, class _Traits = char_traits<_CharT>>
+//   class ostream_joiner;
+//
+//   ostream_joiner & operator*() noexcept
+//     returns *this;
+
+#include <experimental/iterator>
+#include <iostream>
+#include <cassert>
+
+#include "test_macros.h"
+
+namespace exp = std::experimental;
+
+template <class Delim, class CharT, class Traits>
+void test ( exp::ostream_joiner<Delim, CharT, Traits> &oj ) {
+    static_assert((noexcept(*oj)), "" );
+    exp::ostream_joiner<Delim, CharT, Traits> &ret = *oj;
+    assert( &ret == &oj );
+    }
+
+int main () {
+
+    { exp::ostream_joiner<char>         oj(std::cout, '8');                 test(oj); }
+    { exp::ostream_joiner<std::string>  oj(std::cout, std::string("9"));    test(oj); }
+    { exp::ostream_joiner<std::wstring> oj(std::cout, std::wstring(L"10")); test(oj); }
+    { exp::ostream_joiner<int>          oj(std::cout, 11);                  test(oj); }
+
+    { exp::ostream_joiner<char, wchar_t>         oj(std::wcout, '8');                 test(oj); }
+    { exp::ostream_joiner<std::string, wchar_t>  oj(std::wcout, std::string("9"));    test(oj); }
+    { exp::ostream_joiner<std::wstring, wchar_t> oj(std::wcout, std::wstring(L"10")); test(oj); }
+    { exp::ostream_joiner<int, wchar_t>          oj(std::wcout, 11);                  test(oj); }
+    }