54 lines
1.2 KiB
C++
54 lines
1.2 KiB
C++
import <print>;
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import <type_traits>;
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template <bool param1 = false, bool param2 = false>
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struct Builder;
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template <bool enabled>
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struct BuildMixin {};
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template <>
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struct BuildMixin<true> {
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auto build(this auto&& self) { return self.p1 + self.p2; }
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};
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template <bool enabled>
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struct Param1Mixin {};
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template <>
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struct Param1Mixin<false> {
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auto fill_param1(this auto&& self) {
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self.p1 = 1;
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return Builder<true, std::remove_reference_t<decltype(self)>::param2_v>(
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self);
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}
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};
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template <bool enabled>
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struct Param2Mixin {};
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template <>
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struct Param2Mixin<false> {
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auto fill_param2(this auto&& self) {
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self.p2 = 1;
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return Builder<std::remove_reference_t<decltype(self)>::param1_v, true>(
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self);
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}
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};
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template <bool param1, bool param2>
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struct Builder : BuildMixin<param1 && param2>,
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Param1Mixin<param1>,
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Param2Mixin<param2> {
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const constinit static auto param1_v = param1;
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const constinit static auto param2_v = param2;
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int p1;
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int p2;
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Builder() : p1(0), p2(0) {}
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Builder(auto&& other) : p1(other.p1), p2(other.p2) {}
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};
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auto main() -> int {
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Builder builder;
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auto ret = builder.fill_param1().fill_param2().build();
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std::println("{}", ret);
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}
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