import std.datetime, std.algorithm, std.typecons, std.stdio;

auto either(Keys...)(Keys keys)
{
    static struct Result
    {
        bool opIn_r(Key)(Key key)
        {
            foreach (k; keys) {
                if (k == key) {
                    return true;
                }
            }
            return false;
        }
        private Keys keys;
    }
    return Result(keys);
} 

struct ctEither(keys...) {
    @safe bool opBinaryRight(string op:"in", T)(in T x) const pure nothrow {
        foreach (k; keys)
            if (x == k)
                return true;
        return false;
    }
}

struct ctEither2(keys...) {
    @safe bool opBinaryRight(string op:"in", T)(in T x) const pure nothrow {
        switch (x) {
            default:
                return false;
            foreach (k; keys) {
                case k:
                    return true;
            }
        }
        return false;
    }
}

__gshared int p = 1234567890;

void a() {
    assert(p !in ctEither!(1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789)() );
}
void b() {
    assert(p !in either(1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789));
}
void c() {
    assert(![1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789].canFind(p));
}
void d() {
    assert(!(p == 1 || p == 12 || p == 123 || p == 1234 || p == 12345 || p == 123456 || p == 1234567 || p == 12345678 || p == 123456789));
}
void e() {
    assert(p !in ctEither2!(1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789)() );
}
void main() {
    writeln( benchmark!c(1_000_000)[0].to!("msecs", int) );
     
    writeln( benchmark!a(1_000_000)[0].to!("msecs", int) );
    writeln( benchmark!b(1_000_000)[0].to!("msecs", int) );
    writeln( benchmark!d(1_000_000)[0].to!("msecs", int) );
    writeln( benchmark!e(1_000_000)[0].to!("msecs", int) );
}