2 Copyright 2010 Neil Groves
3 Distributed under the Boost Software License, Version 1.0.
4 (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 [section:map_keys map_keys]
10 [[Pipe] [`rng | boost::adaptors::map_keys`]]
11 [[Function] [`boost::adaptors::keys(rng)`]]
14 * [*Precondition:] The `value_type` of the range is an instantiation of `std::pair`.
15 * [*Postcondition:] For all elements `x` in the returned range, `x` is the result of `y.first` where `y` is the corresponding element in the original range.
16 * [*Range Category:] __single_pass_range__
17 * [*Range Return Type:] `boost::select_first_range<decltype(rng)>`
18 * [*Returned Range Category:] The range category of `rng`.
20 [section:map_keys_example map_keys example]
21 [import ../../../test/adaptor_test/map_keys_example.cpp]
25 This would produce the output:
27 0,1,2,3,4,5,6,7,8,9,