Ichthyostega
555af315b3
- remove obsolete configuration settings - walk through all settings according to the documentation https://www.doxygen.nl/manual/config.html - now try to use the new feature to rely on Clang for C++ parsing - walk through the doxygen-warnings.txt and fix some obvious misspellings and structural problems in the documentation comments. With Debian-Trixie, we are now using Doxygen 1.9.8 — which produces massively better results in various fine points. However, there are still problems with automatic cross links, especially from implementation to the corresponding test classes.
87 lines
2.8 KiB
C++
87 lines
2.8 KiB
C++
/*
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UTIL-TUPLE.hpp - helpers and convenience shortcuts for working with tuples
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Copyright (C)
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2023, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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*/
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/** @file util-tuple.hpp
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** Some small helpers and convenience shortcuts to simplify working with
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** tuples and sequences (given by iterator). While tuples and sequences
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** are fundamentally different insofar a tuple has a fixed structure (and
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** may hold elements of different type), sometimes it can be convenient to
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** treat a tuple like a sequence (especially a tuple holding elements of a
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** single type. Notably, an iterator can be unloaded into a fixed-size tuple,
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** which in turn can than be used in a structural binding to unpack references
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** to the elements into scoped variables. Obviously, the meaning of the elements
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** in the sequence must be fixed and predetermined -- which is often the case
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** when dealing with tests or communication protocols.
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**
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** @see util-tuple-test.cpp
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** @see util-coll.hpp
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**
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*/
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#ifndef UTIL_TUPLE_H
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#define UTIL_TUPLE_H
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#include <tuple>
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#include <utility>
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namespace util {
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namespace { // recursive builder helper to unpack a sequence...
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template<size_t N>
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using cnt_ = std::integral_constant<size_t, N>;
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template<class SEQ>
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inline auto
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_buildSeqTuple (cnt_<0>, SEQ&&)
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{
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return std::tuple<>{};
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}
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template<size_t N, class SEQ>
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inline auto
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_buildSeqTuple (cnt_<N>, SEQ&& iter)
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{
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auto prefixTuple = std::tie (*iter);
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++iter;
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return std::tuple_cat (prefixTuple, _buildSeqTuple (cnt_<N-1>{}, std::forward<SEQ> (iter)));
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}
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}//(End) unpacking helper
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/**
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* Unpack an iterator to build a fixed-size std::tuple of references
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* @tparam N (mandatory) defines the number of elements to unpack; can be zero
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* @param iter anything compliant to the Lumiera Forward Iterator protocol
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* @warning since the implementation uses `std::tie (*iter)`, a _reference_ is
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* stored, which may lead to strange and dangerous behaviour if the given
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* iterator exposes a reference to mutable internal state (e.g. "state core").
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* Moreover, it is assumed the iterator yields enough values to fill the new
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* tuple, and this is not checked; an empty or exhausted iterator might throw,
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* or yield otherwise undefined behaviour.
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*/
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template<size_t N, class SEQ>
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auto
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seqTuple (SEQ&& iter)
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{
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return _buildSeqTuple (cnt_<N>{}, std::forward<SEQ> (iter));
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}
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} // namespace util
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#endif /*UTIL_TUPLE_H*/
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