Haskell's Kind System Lets You Microwave Any Bowl
Types of types: Haskell's Kind system
While adding typed configuration to his Redis server clone, the author explores Haskell's Kind system from values to types to kinds. He explains higher-kinded types (HKTs) and higher-kinded data (HKD), showing how a single data type can serve as a default config, a partial form, or a set of labels by varying the type constructor. The bowl analogy makes it clear: certify the bowl, not the soup.
In non-technical terms, take a bowl for eating. Make the bowl itself microwave-safe and you can use it to warm any food you put in it.