Re: extend "in" to all array types

[Tobias Pankrath]

On Wednesday, 15 January 2014 at 17:13:37 UTC, Meta wrote:

auto inWrap(T)(T[] arr)
{
    static struct InWrapper
    {
        import std.typecons: Nullable;

        private T[] payload;

        Nullable!size_t opBinaryRight(string op: "in")(T val)
        {
            Nullable!size_t index;
            foreach (i, element; payload)
            {
                if (element == val)
                {
                    index = i;
                                        
                                        return index;
                }
            }

            return index;
        }
    }

    return InWrapper(arr);
}

void main()
{
    auto arr = [0, 1, 2, 3, 4];
        auto i = 2 in arr.inWrap;
    assert(!i.isNull);
        assert(i == 2);
}

The in-operator should return T* for consistency with the 
build-in ones.