* Several range algorithms
In `<algorithm>`, implement:
* the generic algorithm result types from P2106R0 (lines 75-227)
* `ranges::for_each` and its result alias `for_each_result` (lines 289-322)
* `ranges::for_each_n` and its result alias `for_each_result_n` (lines 324-351) from P1243R4
* `ranges::find` (lines 353-384)
* `ranges::find_if` (lines 396-426)
* `ranges::find_if_not` (lines 454-484)
* `ranges::count` (lines 526-568)
* `ranges::count_if` (lines 587-617)
* `ranges::mismatch` and its result alias `mismatch_result` (lines 798-891)
* `ranges::equal` (lines 893-980)
* `ranges::all_of` (lines 1006-1033)
* `ranges::any_of` (lines 1060-1087)
* `ranges::none_of` (lines 1114-1141)
* `ranges::copy` and its result alias `copy_result` (lines 1143-1175)
* `ranges::copy_n` and its result alias `copy_n_result` (lines 1177-1207)
* `ranges::copy_if` and its result alias `copy_if_result` (lines 1262-1302)
In `<concepts>`:
* implement LWG-3194 which includes the resolution of LWG-3151 (lines 51-53)
* LWG-3175 has been merged, remove conditional implementation (line 183)
* replace `boolean` concept with _`boolean-testable`_ concept from P1964R2 (lines 198-237, 283)
* move `movable` (pun intended) into synopsis order (lines 254-256)
* Modify concept `copyable` per P2102R0 (lines 260-261)
* Implement concept `equivalence_relation` from P1716R3 (lines 290-293)
In `<xutility>`:
* promote `identity` from `<functional>` for visibility in `<algorithm>` (lines 160-168)
* promote `common_range` from `<ranges>` for visibility in `<algorithm>` (lines 3091-3095)
* remove LWG-3247 and LWG-3299 annotations (lines 622, 626, and 963)
* prefix `indirectly_` to the names of `readable_traits`, `readable`, and `writable` (a great many lines); and modify `iter_value_t` (lines 366-367), `iter_reference_t` (lines ), `iter_difference_t`, `iter_rvalue_reference_t`, `indirectly_readable` (lines 688-701) and `indirectly_swappable` per P1878R1
* define alias template `_Make_unsigned_like_t` to implement P1522R1's _`make-unsigned-like-t`_ (it does nothing interesting yet, since we provide no integer-class types) (lines 727-729)
* implement the "Indirect callable" concepts `indirectly_unary_invocable`, `indirectly_regular_unary_invocable`, `indirect_unary_predicate`, `indirect_binary_predicate`, `indirect_equivalence_relation`, `indirect_strict_weak_order`, and helpers `indirect_result_t` and `projected` (lines 852-926)
* implement `indirectly_copyable` and `indirectly_copyable_storable` concepts (lines 939-952)
* implement `indirectly_swappable`, `indirectly_comparable`, `permutable`, `mergeable`, and `sortable` concepts (lines 1032-1061)
* rename `safe_range` and `enable_safe_range` to `borrowed_range` and `enable_borrowed_range` per LWG-3379 (lines 2168-2173 and 2327-2330)
* remove "Implements D2091R0" comments (various lines in 2175-2710)
* add `ranges::data` to the list of access CPOs that hard error for arrays of incomplete element types (lines 2204-2205 and 2277-2278)
* `ranges::empty` rejects arrays of unbound bound per P2091R0 (lines 2664-2692)
* implement concept `_Not_same_as` (the exposition-only _`not-same-as`_ from the working draft) (lines 3087-3089)
* implement `ranges::dangling` (lines 3097-3102)
* implement `ranges::borrowed_iterator_t` (lines 3104-3106)
In `<yvals_core.h>`:
* Indicate implementation of:
* P1207R4 Movability of Single-Pass Iterators
* P1248R1 Fixing Relations
* P1474R1 Helpful Pointers For contiguous_iterator
* P1716R3 Range Comparison Algorithms Are Over-Constrained
* P1878R1 Constraining Readable Types
* P1964R2 Replacing `boolean` with _`boolean-testable`_
* P2091R0 Fixing Issues With Range Access CPOs
* P2102R0 Make "implicit expression variations" More Explicit
* and partial implementation of:
* P1243R4 Rangify New Algorithms
* remove conditional definition of `_HAS_STD_BOOLEAN` (we never has `std::boolean` now)
`tests/std/include/instantiate_algorithms.hpp`:
* define non-movable type `Immobile`, and use it to ensure that standard algorithms neither copy nor move random number generators nor uniform random bit generators
Add header `tests/std/include/range_algorithm_support.hpp` with support machinery for the ranges algorithm tests. It notably defines:
* `is_permissive` for determining whether we are compiling in MSVC's permissive mode (lines 18-37)
* A class template `borrowed<bool>` whose specializations always model `range` and model `borrowed_range` iff the template parameter is `true` (lines 39-46)
* Function objects `get_first` and `get_second` which project the pertinent member from `pair` arguments (lines 48-54)
* A class template `move_only_range<T>` which adapts a `contiguous_range` of `T` into a move-only `view` with move-only `input_iterator`s (lines 56-150)
* A "phony" iterator class template `test_iterator` with tunable category, value type, and difference capability for instantiation tests (lines 152-363)
* A similar "phony" class template `test_range` with tunable category, size, and commonality (i.e., is the sentinel type the same as the iterator type) (lines 365-423)
* "phony" predicate and projection types for instantiation tests (lines 425-442)
* combinatoric instantiation machinery for instantiation tests that instantiate with all interesting kinds of output iterators or input ranges (lines 444-529)
A new compile-only test `tests/std/tests/P0896R4_ranges_algorithm_machinery` which covers:
* `indirectly_unary_invocable`/`indirectly_regular_unary_invocable`
* `indirect_unary_predicate`/`indirect_binary_predicate`/`indirect_result_t`
* `projected`
* `indirectly_copyable`/`indirectly_swappable`/`indirectly_comparable`
* `dangling`/`borrowed_iterator_t`
* the result types `in_found_result`/`in_fun_result`/`in_in_result`/`in_out_result`/`in_in_out_result`/`in_out_out_result`/`min_max_result`
Very simple smoke and instantiation tests for the 15 new algorithms in:
* `tests/std/tests/P0896R4_ranges_alg_all_of`
* `tests/std/tests/P0896R4_ranges_alg_any_of`
* `tests/std/tests/P0896R4_ranges_alg_copy`
* `tests/std/tests/P0896R4_ranges_alg_copy_if`
* `tests/std/tests/P0896R4_ranges_alg_copy_n`
* `tests/std/tests/P0896R4_ranges_alg_count`
* `tests/std/tests/P0896R4_ranges_alg_count_if`
* `tests/std/tests/P0896R4_ranges_alg_equal`
* `tests/std/tests/P0896R4_ranges_alg_find`
* `tests/std/tests/P0896R4_ranges_alg_find_if`
* `tests/std/tests/P0896R4_ranges_alg_find_if_not`
* `tests/std/tests/P0896R4_ranges_alg_for_each`
* `tests/std/tests/P0896R4_ranges_alg_for_each_n`
* `tests/std/tests/P0896R4_ranges_alg_mismatch`
* `tests/std/tests/P0896R4_ranges_alg_none_of`
Resolves:
* #537 `<concepts>`: LWG-3175 has been accepted, so we should remove commented-out code
* #540 LWG-3194 `ConvertibleTo` prose does not match code
* #546 LWG-3379 `safe` in several library names is misleading
* #559 P1964R2 "Replacing `boolean` with _`boolean-testable`_"
* #561 P2102R0 "Making 'Implicit Expression Variations' More Explicit"
* #563 P2091R0 "Fixing Issues With Range Access CPOs"
Casey Carter
Michael Schellenberger Costa
Daniel Marshall