Search code examples
dictionarytuplesreason

How to create Map of tuples in ReasonML?

I'm very new to Reason. I have a tuple containing two strings and want to make a Map where the keys are of that tuple type.

How should I go about doing it?

Solution

  • Map.Make is a functor, which means it expects a module as its argument, not a type. The module argument must conform to the OrderedType signature:

    module type OrderedType = {
  type t
  let compare : (t, t) => int
}

    In your case that would be something like:

    module TuplesMap = Map.Make({
  type t = (string, string)
  let compare = (a, b) => ...
});

    Then all you need to do is to implement the compare function.