The case expression is the most common kind of flow control in Gleam code. It is similar to `switch` in some other languages, but more powerful than most.

It allows the programmer to say "if the data has this shape then run this code", a process called called pattern matching.

Gleam performs exhaustiveness checking to ensure that the patterns in a case expression cover all possible values. With this you can have confidence that your logic is up-to-date for the design of the data you are working with.

Try commenting out patterns or adding new redundant ones, and see what problems the compiler reports.