Treasure Chest

pub type Box(a) {
  Box(a)
}

Box("Hello, Joe!") // The type is Box(String)

Box(42) // The type is Box(Int)

pub type Pair(a, b) {
  Pair(a, b)
}

pub fn twice(value: a, f: fn(a) -> b) -> b {
  f(value)
  f(value)
}

// The type is fn(String, fn(String) -> Nil) -> Nil
twice("Hello, Joe!", io.println)

Instructions

In this exercise you're going to write a generic (/ magical!) TreasureChest, to store some treasure.

1. Define the TreasureChest generic custom type

Define a TreasureChest custom type with a single variant.

The variant should have an associated String value, which will be used to store the password of the treasure chest.

The variant should also have an associate generic value, which will be used to store the treasure. This value is generic so that the treasure can be anything.

2. Define the UnlockResult type

Define a UnlockResult custom type with two variants.

The first variant should be Unlocked, and should hold generic value, which will be used to store the treasure.

The second variant should be WrongPassword, which holds no values.

3. Define the get_treasure function

This function should take two parameters

• a TreasureChest generic custom type
• a String (for trying a password)

This function should check the provided password attempt against the String in the TreasureChest.

The function should return a UnlockResult.

If the passwords match then return Unlocked with the generic value from the TreasureChest (the treasure!)

If the passwords do not match then return WrongPassword.