val index = 5;
val tuple1 = (1,2,3,4,5,6,7,8,9,10);

val correctValue = #index tuple1 ??

- {1 = 1, 2 = "foo", 3 = 42.0};
val it = (1,"foo",42.0) : int * string * real

fn {id=var, ...} => var