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How to create a switch with variable patterns

I want to build a function, for example:

template< int ... values> constexpr bool check( int i ) noexcept { switch(i) { case values[0]: case values[1]: ... case values[n-1] : // only illustrated. return true; default: return false; } }

Can I perform this function?

UPDATE: thanks, now I know how to implement:

 template< int ... values> struct checker; template< int head, int ... tail> struct checker<head, tail...> { static constexpr bool apply( int i ) noexcept { return i == head || checker<tail...>::apply(i); } }; template<> struct checker<> { static constexpr bool apply( int ) noexcept { return false; } }; template< int ... values > constexpr bool check(int i) noexcept { return checker<values...>::apply(i); }

UPDATE2: I don't know if this is good or not, but I found this solution:

  template<size_t N> constexpr bool any_of( bool( && array)[N], size_t index = 0) noexcept { return (index == N ) ? false : ( array[index] || any_of( std::forward< decltype(array)>(array), 1+index) ); } template< int ... values > constexpr bool check(int i) noexcept { using list = bool[sizeof...(values)]; return any_of( list{ ( i == values) ... } ); } template<> constexpr bool check <>(int i) noexcept { return false; }
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1 answer

I don't think you can use the switch syntax in any way. But this should work:

 template < int head, int ... values > struct checker { static constexpr bool value(int i) noexcept { return i == head || checker<values...>::value(i); } }; template < int head > struct checker<head> { static constexpr bool value(int i) noexcept { return i == head; } }; template< int ... values> constexpr bool check( int i ) noexcept { return checker<values...>::value(i); }

Living example

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