corecel/io/Join.hh

0001 //----------------------------------*-C++-*----------------------------------//
0002 // Copyright 2020-2024 UT-Battelle, LLC, and other Celeritas developers.
0003 // See the top-level COPYRIGHT file for details.
0004 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0005 //---------------------------------------------------------------------------//
0006 //! \file corecel/io/Join.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include "detail/Joined.hh"  // IWYU pragma: export
0011
0012 namespace celeritas
0013 {
0014 //---------------------------------------------------------------------------//
0015 /*!
0016  * Join items, similar to python's "str.join" method.
0017  *
0018  * This utility function will concatenate the values passed to it. The given
0019  * conjunction ONLY appears between values.
0020  *
0021  * \code
0022    cout << celeritas::join(foo.begin(), foo.end(), ", ") << endl
0023    \endcode
0024  *
0025  * The result is a thin class that is streamable. (It can explicitly be
0026  * converted to a string with the
0027  * \c to_string method). By doing this instead of returning a std::string,
0028  * large and dynamic containers can be e.g. saved to disk.
0029  */
0030 template<class InputIterator, class Conjunction>
0031 detail::Joined<InputIterator, Conjunction, detail::StreamValue>
0032 join(InputIterator first, InputIterator last, Conjunction&& conjunction)
0033 {
0034     return {first, last, std::forward<Conjunction>(conjunction), {}};
0035 }
0036
0037 //---------------------------------------------------------------------------//
0038 /*!
0039  * Join items transformed by a helper functor.
0040  *
0041  * This joins all given elements, inserting conjunction betwen them. The 'op'
0042  * operator must transform each element into a printable object. For example,
0043  * \code
0044       [](const std::pair<int, int>& item) { return item->first; }
0045  * \endcode
0046  * could be used to get the 'key' item of a map.
0047  */
0048 template<class InputIterator, class Conjunction, class UnaryOperation>
0049 detail::Joined<InputIterator, Conjunction, detail::UnaryToStream<UnaryOperation>>
0050 join(InputIterator first,
0051      InputIterator last,
0052      Conjunction&& conjunction,
0053      UnaryOperation&& op)
0054 {
0055     return {first,
0056             last,
0057             std::forward<Conjunction>(conjunction),
0058             {std::forward<UnaryOperation>(op)}};
0059 }
0060
0061 //---------------------------------------------------------------------------//
0062 /*!
0063  * Join using a functor that takes (ostream&, value).
0064  */
0065 template<class InputIterator, class Conjunction, class StreamOp>
0066 detail::Joined<InputIterator, Conjunction, StreamOp>
0067 join_stream(InputIterator first,
0068             InputIterator last,
0069             Conjunction&& conjunction,
0070             StreamOp&& op)
0071 {
0072     return {first,
0073             last,
0074             std::forward<Conjunction>(conjunction),
0075             std::forward<StreamOp>(op)};
0076 }
0077
0078 //---------------------------------------------------------------------------//
0079 }  // namespace celeritas