Add Allergies exercise

[isaacvando]

No description provided.

[ageron]

Nice! I feel like the list function could be simpler:

list : U64 -> Set Allergen
list = \score ->
    [Eggs, Peanuts, Shellfish, Strawberries, Tomatoes, Chocolate, Pollen, Cats]
    |> List.walk (score, Set.empty {}) \(bits, allergies), allergy ->
        updatedAllergies = if bits % 2 == 0 then allergies else allergies |> Set.insert allergy
        (bits // 2, updatedAllergies)
    |> .1

This removes the need for the functions largestPowerOfTwo and values.

Also, if list returns a Set, shouldn't we call it set?

[ageron]

Or maybe using a record rather than a tuple for the state would be clearer?

list : U64 -> Set Allergen
list = \score ->
    [Eggs, Peanuts, Shellfish, Strawberries, Tomatoes, Chocolate, Pollen, Cats]
    |> List.walk {bits: score, allergies: Set.empty {}} \{bits, allergies}, allergy ->
        updatedAllergies = if bits % 2 == 0 then allergies else allergies |> Set.insert allergy
        {bits: bits // 2, allergies: updatedAllergies}
    |> .allergies

[isaacvando]

Wow that solution is so much nicer! I was definitely over complicating things. Thanks @ageron! 😄
I also renamed the function to set and decreased the difficulty.