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Diffstat (limited to '')
-rw-r--r-- | third_party/immer/test/transient_tester.hpp | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/third_party/immer/test/transient_tester.hpp b/third_party/immer/test/transient_tester.hpp new file mode 100644 index 000000000000..3cf891bef957 --- /dev/null +++ b/third_party/immer/test/transient_tester.hpp @@ -0,0 +1,54 @@ +// +// immer: immutable data structures for C++ +// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente +// +// This software is distributed under the Boost Software License, Version 1.0. +// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt +// + +#pragma once + +#include "dada.hpp" + +namespace { + +template <typename VP, typename VT> +struct transient_tester +{ + VP vp; + VT vt; + dadaism d = {}; + bool transient = false; + + transient_tester(VP vp) + : vp{vp} + , vt{vp.transient()} + {} + + bool step() + { + auto s = d.next(); + if (soft_dada()) { + auto new_transient = !transient; + try { + if (new_transient) + vt = vp.transient(); + else + vp = vt.persistent(); + } catch (const dada_error&) { + return false; + } + transient = new_transient; + return true; + } else + return false; + } +}; + +template <typename VP> +transient_tester<VP, typename VP::transient_type> as_transient_tester(VP p) +{ + return {std::move(p)}; +} + +} // anonymous namespace |