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Telegram/ThirdParty/range-v3/include/range/v3/functional/on.hpp

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+/// \file
+// Range v3 library
+//
+//  Copyright Eric Niebler 2013-present
+//
+//  Use, modification and distribution is subject to the
+//  Boost Software License, Version 1.0. (See accompanying
+//  file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//
+// Project home: https://github.com/ericniebler/range-v3
+//
+#ifndef RANGES_V3_FUNCTIONAL_ON_HPP
+#define RANGES_V3_FUNCTIONAL_ON_HPP
+
+#include <concepts/concepts.hpp>
+
+#include <range/v3/detail/config.hpp>
+#include <range/v3/functional/invoke.hpp>
+
+#include <range/v3/detail/prologue.hpp>
+
+namespace ranges
+{
+    /// \addtogroup group-functional
+    /// @{
+    template<typename Fn1, typename Fn2>
+    struct transformed
+    {
+    private:
+        RANGES_NO_UNIQUE_ADDRESS
+        Fn1 first_;
+        RANGES_NO_UNIQUE_ADDRESS
+        Fn2 second_;
+
+    public:
+        transformed() = default;
+        constexpr transformed(Fn1 fn1, Fn2 fn2)
+          : first_(static_cast<Fn1 &&>(fn1))
+          , second_(static_cast<Fn2 &&>(fn2))
+        {}
+        // clang-format off
+        template<typename... Args>
+        auto CPP_auto_fun(operator())(Args &&... args)
+        (
+            return invoke(first_, invoke(second_, static_cast<Args &&>(args)...))
+        )
+        template<typename... Args>
+        auto CPP_auto_fun(operator())(Args &&... args)(const)
+        (
+            return invoke((Fn1 const &)first_,
+                          invoke((Fn2 const &)second_, static_cast<Args &&>(args))...)
+        )
+        // clang-format on
+    };
+
+    struct on_fn
+    {
+        template<typename Fn1, typename Fn2>
+        constexpr transformed<Fn1, Fn2> operator()(Fn1 fn1, Fn2 fn2) const
+        {
+            return transformed<Fn1, Fn2>{detail::move(fn1), detail::move(fn2)};
+        }
+    };
+
+    /// \ingroup group-functional
+    /// \sa `on_fn`
+    RANGES_INLINE_VARIABLE(on_fn, on)
+    /// @}
+} // namespace ranges
+
+#include <range/v3/detail/epilogue.hpp>
+
+#endif