stabilize build system: depends, installer, boost/bdb fixes, cross targets groundwork

2026-02-24 18:38:47 +00:00
parent da8c28aaeb
commit 65cb2619a7
13106 changed files with 2484322 additions and 1804 deletions
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+/*!
+@file
+Forward declares `boost::hana::cycle`.
+
+@copyright Louis Dionne 2013-2017
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef BOOST_HANA_FWD_CYCLE_HPP
+#define BOOST_HANA_FWD_CYCLE_HPP
+
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/when.hpp>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! Combine a monadic structure with itself `n` times.
+    //! @ingroup group-MonadPlus
+    //!
+    //! Given a monadic structure `xs` and a non-negative number `n`,
+    //! `cycle` returns a new monadic structure which is the result of
+    //! combining `xs` with itself `n` times using the `concat` operation.
+    //! In other words,
+    //! @code
+    //!     cycle(xs, n) == concat(xs, concat(xs, ... concat(xs, xs)))
+    //!                                       // ^^^^^ n times total
+    //! @endcode
+    //!
+    //! Also note that since `concat` is required to be associative, we
+    //! could also have written
+    //! @code
+    //!     cycle(xs, n) == concat(concat(... concat(xs, xs), xs), xs)
+    //!                               // ^^^^^ n times total
+    //! @endcode
+    //!
+    //! If `n` is zero, then the identity of `concat`, `empty`, is returned.
+    //! In the case of sequences, this boils down to returning a sequence
+    //! containing `n` copies of itself; for other models it might differ.
+    //!
+    //!
+    //! Signature
+    //! ---------
+    //! Given an `IntegralConstant` `C` and a `MonadPlus` `M`, the signature is
+    //! @f$ \mathrm{cycle} : M(T) \times C \to M(T) @f$.
+    //!
+    //! @param xs
+    //! A monadic structure to combine with itself a certain number of times.
+    //!
+    //! @param n
+    //! A non-negative `IntegralConstant` representing the number of times to
+    //! combine the monadic structure with itself. If `n` is zero, `cycle`
+    //! returns `empty`.
+    //!
+    //!
+    //! Example
+    //! -------
+    //! @include example/cycle.cpp
+#ifdef BOOST_HANA_DOXYGEN_INVOKED
+    constexpr auto cycle = [](auto&& xs, auto const& n) {
+        return tag-dispatched;
+    };
+#else
+    template <typename M, typename = void>
+    struct cycle_impl : cycle_impl<M, when<true>> { };
+
+    struct cycle_t {
+        template <typename Xs, typename N>
+        constexpr auto operator()(Xs&& xs, N const& n) const;
+    };
+
+    constexpr cycle_t cycle{};
+#endif
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_FWD_CYCLE_HPP